A sustainable cropping system is needed to ensure profitable, productive and less risky crop production, particularly when the agricultural sector is experiencing climatic uncertainty and price volatility. Hence, the study aims to identify paddy-based cropping systems and their sustainability in the Nellore district of Andhra Pradesh. The study is based on primary data collected during 2022-23 with the help of a pre-structured schedule. The major cropping systems based on paddy were identified as system Ⅰ (paddy-groundnut), cropping system Ⅱ (paddy-paddy), & cropping system Ⅲ (paddy-cotton). The profitability analysis revealed that the gross returns for cropping systems I, II and III were computed to be Rs. 281916.83, Rs. 259072.90 and Rs. 330072.45. The farmers realized the highest net income, Rs. 169222.62, under cropping system III. The net returns for the cropping systems Ⅰ and Ⅱ were obtained as Rs. 141282.24 and Rs. 127048.48, respectively. The sustainability indices of paddy-groundnut (cropping system I), paddy-paddy (cropping system II) and cropping system III (paddy-cotton) were computed as 42.88%, 50.86% and 60.93%, respectively, and the paddy-cotton cropping system came out as the most profitable and sustainable in the study area. The regression analysis revealed that factors like returns to cost ratio and the cost used for environmentally friendly inputs relative to the overall cost of cultivation were found significant in all three cropping systems.