diff --git a/esphome/components/pcf85063/pcf85063.cpp b/esphome/components/pcf85063/pcf85063.cpp
index c0825d9..b402f6e 100644
--- a/esphome/components/pcf85063/pcf85063.cpp
+++ b/esphome/components/pcf85063/pcf85063.cpp
@@ -125,7 +125,7 @@ void PCF85063Component::set_timer_interrupt_mode_(PCF85063ATimerInterruptMode_t
 }
 
 bool PCF85063Component::write_timer_() {
-  if (!this->write_bytes(0x10, &this->pcf85063_.raw[0x03], 2)) {
+  if (!this->write_bytes(0x10, &this->pcf85063_.raw[0x10], 2)) {
     ESP_LOGE(TAG, "Can't write I2C data.");
     return false;
   }