Plastic pollution is a global problem, and researchers are trying to find an alternative for plastics. Bioplastic, biodegradable plastic, bio-based plastic, and compostable plastic are suggested as alternatives to the normal plastic. This work focuses on the changes that occurred during the composting of compostable plastics with kitchen waste in different proportions for 3-month duration. Tests also included composting at elevated temperature of 52–55 °C. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) results showed new peaks of different functional groups because of degradation, and thermogravimetric analysis (TGA) results showed up to 11.0% change in mass reduction. There was no noticeable change in biodegradation at high temperature. The result showed the biodegradability of compostable plastic and the need for long-term study.