diff --git a/app/src/main/java/com/p_vacho/neat_calendar/activities/CreateCategoryActivity.kt b/app/src/main/java/com/p_vacho/neat_calendar/activities/CreateCategoryActivity.kt
index 42a5765..41dda6e 100644
--- a/app/src/main/java/com/p_vacho/neat_calendar/activities/CreateCategoryActivity.kt
+++ b/app/src/main/java/com/p_vacho/neat_calendar/activities/CreateCategoryActivity.kt
@@ -1,17 +1,48 @@
 package com.p_vacho.neat_calendar.activities
 
+import android.content.Intent
+import android.content.res.ColorStateList
+import android.graphics.Color
 import android.os.Bundle
+import android.util.Log
+import android.widget.Toast
 import androidx.activity.enableEdgeToEdge
 import androidx.appcompat.app.AppCompatActivity
+import androidx.core.content.ContextCompat
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowInsetsCompat
+import androidx.lifecycle.lifecycleScope
+import com.github.dhaval2404.colorpicker.ColorPickerDialog
+import com.google.android.material.button.MaterialButton
+import com.google.android.material.textfield.TextInputEditText
+import com.google.gson.Gson
 import com.p_vacho.neat_calendar.R
+import com.p_vacho.neat_calendar.api.RetrofitClient
+import com.p_vacho.neat_calendar.api.models.CategoryRequest
+import com.p_vacho.neat_calendar.api.models.CategoryResponse
+import com.p_vacho.neat_calendar.api.models.PartialCategoryRequest
+import com.p_vacho.neat_calendar.api.models.ValidationError
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import retrofit2.HttpException
+import kotlin.properties.Delegates
 
 enum class CategoryMode {
     CREATE, EDIT
 }
 
 class CreateCategoryActivity : AppCompatActivity() {
+    private var selectedColor by Delegates.notNull<Int>()
+    private var existingCategory: CategoryResponse? = null
+    private lateinit var mode: CategoryMode
+
+    // UI components
+    private lateinit var etCategoryName: TextInputEditText
+    private lateinit var btnColorPicker: MaterialButton
+    private lateinit var btnSaveCategory: MaterialButton
+    private lateinit var btnCancel: MaterialButton
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
@@ -21,5 +52,107 @@ class CreateCategoryActivity : AppCompatActivity() {
             v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
             insets
         }
+
+        initializeViews()
+        mode = intent.getStringExtra("mode")!!.let { CategoryMode.valueOf(it) }
+
+        if (mode == CategoryMode.EDIT) {
+            @Suppress("DEPRECATION")
+            existingCategory = intent.getParcelableExtra("category")!!
+
+            etCategoryName.setText(existingCategory?.name)
+            selectedColor = existingCategory?.color?.toArgb() ?: ContextCompat.getColor(this, R.color.category_indicator_color)
+            btnSaveCategory.setText(R.string.update_category)
+        } else {
+            selectedColor = ContextCompat.getColor(this, R.color.category_indicator_color)
+        }
+
+        btnColorPicker.iconTint = ColorStateList.valueOf(selectedColor)
+        setupListeners()
     }
-}
\ No newline at end of file
+
+    private fun initializeViews() {
+        etCategoryName = findViewById(R.id.etCategoryName)
+        btnColorPicker = findViewById(R.id.btnColorPicker)
+        btnSaveCategory = findViewById(R.id.btnSaveCategory)
+        btnCancel = findViewById(R.id.btnCancel)
+    }
+
+    private fun setupListeners() {
+        btnColorPicker.setOnClickListener { openColorPickerDialog() }
+        btnSaveCategory.setOnClickListener { saveCategory() }
+        btnCancel.setOnClickListener { finish() }
+    }
+
+    private fun saveCategory() {
+        val categoryName = etCategoryName.text.toString().trim()
+        if (categoryName.isEmpty()) {
+            Toast.makeText(this, getString(R.string.please_enter_a_category_name), Toast.LENGTH_SHORT).show()
+            return
+        }
+
+        lifecycleScope.launch(Dispatchers.IO) {
+            try {
+                val resultCategory = if (mode == CategoryMode.CREATE) {
+                    val request =
+                        CategoryRequest(name = categoryName, color = Color.valueOf(selectedColor))
+                    RetrofitClient.categoryService.createCategory(request)
+                } else {
+                    val request = PartialCategoryRequest(
+                        name = categoryName.takeIf { it != existingCategory?.name },
+                        color = Color.valueOf(selectedColor)
+                            .takeIf { it != existingCategory?.color }
+                    )
+                    RetrofitClient.categoryService.updateCategory(existingCategory!!.id, request)
+                }
+
+                withContext(Dispatchers.Main) { handleCategorySaved(resultCategory) }
+            } catch (e: HttpException) {
+                if (e.code() != 422) {
+                    throw e
+                }
+
+                val errorBody = e.response()?.errorBody()?.string()
+                val validationError = Gson().fromJson(errorBody, ValidationError::class.java)
+                val errMsg = validationError.detail.joinToString("\n")
+
+                Log.e("CategoryCreate", "Got HTTP 422: $validationError")
+
+                withContext(Dispatchers.Main) {
+                    Toast.makeText(
+                        this@CreateCategoryActivity,
+                        getString(R.string.failed_to_save_category, errMsg),
+                        Toast.LENGTH_SHORT
+                    ).show()
+                }
+            }
+        }
+    }
+
+    private fun handleCategorySaved(category: CategoryResponse) {
+        Log.w("CreateCategory", "Ending")
+        val intent = Intent().apply {
+            if (mode == CategoryMode.CREATE) {
+                putExtra("newCategory", category)
+                Log.w("CreateCategory", "New")
+            } else {
+                putExtra("editedCategory", category)
+                Log.w("CreateCategory", "Edit")
+            }
+        }
+        setResult(RESULT_OK, intent)
+        finish()
+    }
+
+    private fun openColorPickerDialog() {
+        ColorPickerDialog
+            .Builder(this)
+            .setTitle(getString(R.string.select_color))
+            .setDefaultColor(selectedColor)
+            .setColorListener { color, _ ->
+                selectedColor = color
+                btnColorPicker.iconTint = ColorStateList.valueOf(color)
+            }
+            .show()
+    }
+}
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index ec6aa04..d5151df 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -44,6 +44,7 @@
     <string name="remove_category">Remove the category</string>
     <string name="add_category">Add category</string>
     <string name="update_event">Update Event</string>
+    <string name="update_category">Update Category</string>
     <string name="leave_invited_event">Leave invited event</string>
     <string name="open_app_settings">Open Settings</string>
     <string name="open_notifications">Open Notifications</string>
@@ -97,4 +98,6 @@
     <string name="event_owner_section">Event owner:</string>
     <string name="no_invited_categories_placeholder">You can\'t see categories for invited events</string>
     <string name="edit_category">Edit category</string>
+    <string name="please_enter_a_category_name">Please enter a category name</string>
+    <string name="failed_to_save_category">Failed to save category: %1$s</string>
 </resources>
\ No newline at end of file