Climate control in indoor environments like operation theatres, homes and offices can be done using a PIC microcontroller. The availability of an in-built I2C module, power saving SLEEP mode and the low power consumption of the PIC microcontroller makes it feasible for a cost effective system. Several sensors connected to the PIC microcontroller monitor the climatic conditions within the room. Actuators are used for feedback control. A 3-key keypad user interface is provided along with a 16x2 alphanumeric LCD display. A real time clock (RTC) is interfaced to the microcontroller to enable the system to perform preprogrammed actions. Categories and Subject DescriptorsC.3 Special -Purpose and Application -Based Systemsmicroprocessor/microcomputer applications. General TermsDesign.