This study assessed the relative profitability and social impact of peanut cultivation over Boro rice production in a polder of coastal Bangladesh where there is a scarcity of sweet water for crop cultivation in the Rabi season. Sixty samples from a village namely Sekendarkhali of Amtali Upazila under Barguna district were randomly selected for the study. Data were collected through face-to-face interviews, focus group discussion, and key informant interviews, and different quantitative and qualitative methods were used to explain the data. Cost and return analysis was performed to assess the relative profitability of the two crops. Major findings of the study show that per hectare total costs, gross return, gross margin, and net returns for peanut and Boro production were Tk. 116170 and Tk. 91632; Tk. 132648 and Tk. 52419; Tk. 28540 and Tk. -27628; and Tk. 16478 and Tk. -39203, respectively, which indicate that peanut was more profitable than Boro rice. Moreover, benefit-cost ratios (BCR) of peanut and Boro rice production were found 1.14 and 0.57, respectively indicating peanut production is profitable for farmers in the study area but not the Boro rice production. It was also found that peanut cultivation has some positive social impacts. Adoption of peanut cultivation as a Rabi crop increases the cropping intensity of the study area, creates employment opportunities for both men and women, helps to ensure better nutritional status and better health of the farmers, helps the farmers to stay in the village and to build a better social relationship, increases the income of the farmers, and ensures a better standard of living. The study also identified some problems and constraints faced by the peanut growing farmers and suggested some recommendations to improve the present production of peanuts so that adoption and per hectare yield of peanut would possibly be increased.