We assessed the baseline knowledge and the improvement and retention of knowledge after attending diabetes self-management education (DSME) programs with respect to different socioeconomic status (SES). We also looked into the change in body mass index (BMI), blood pressure, and glycemic parameters after attending the DSME sessions. This was a retrospective, cohort study carried out via chart review based on data collected from manual or electronic medical records (EMR) and questionnaire responses of 160 adult patients with type 2 diabetes (T2D) who attended two DSME sessions with a gap of at least six months. Baseline knowledge on diabetes was uniform (P = 0.06), irrespective of differences in SES, and DSME sessions significantly improved the knowledge in all socioeconomic classes (P value < 0.05 in each SES group). However, SES did have a significant influence on the finally acquired knowledge of diabetes as was evident from the final score after attending two DSME sessions. A significant number of patients (48.1%) from our cohort either improved or retained their knowledge of diabetes over a mean follow-up of 15.5 months. The BMI of our cohort was significantly reduced from baseline to final follow-up (P = 0.016). DSME sessions were effective in improving knowledge and awareness among T2D patients, irrespective of socioeconomic classes in Eastern India. The acquired knowledge from DSME sessions was retained over a long time.