The paper analyses the impacts of climate change and its impact on food security in the Kalapara Upazila of Patuakhali district in Bangladesh. The paper shows current climate change scenarios for Kalapara, analyses the relationship between climate change scenarios and agricultural production and then prescribe adaptive measures to climate change. Historical yearly temperature and rainfall data from Bangladesh Meteorological Department (BMD) and crop yield data from the census of agriculture zilla series, Patuakhali, year book of agricultural statistics and agricultural ministry of Bangladesh were used. A questionnaire survey was also conducted to gather farmer perceptions on climate change in addition focus group discussions were held with selected farmers in the Upazila. The results showed evidence of climate change through analysis of climate data, crop yields and farmers perceptions. Evidence was manifested through the temperature increase, increasing frequency of natural disaster and irregular rainfalls, which are directly influenced the condition of food security of Kalapara Upazila. It was the concluded that climate change occurring in Kalapara Upazila has resulted in significant decline in agricultural production. The paper is also showed the comparison of sources of food and production amount between past and present. The people\'s perceptions show that the temperatures are rising, timely rainfall is not available and crop production seasons are shifting. The lessons show that people are aware of climate change and its impacts on food security. But lack of proper knowledge is the main causes to adapt to these changes.