We conducted a study to determine medications adherence and factors associated with poor adherence in community-dwelling adults with diabetes in southern India. A cross-sectional survey was conducted among 346 diabetes patients selected using multistage cluster sampling. The 8-item Morisky Medication Adherence Scale was used to collect information on adherence. Prevalence of poor adherence was 74% (95% confidence interval = 69.2-78.3). Multiple regression analysis showed that patients using oral hypoglycemic agents, who had lower per capita monthly expenditure, those with irregular blood sugar monitoring, who received limited diabetes management instructions from health professionals, who resorted to only symptomatic management, and those who did not receive family member’s help to remember medications were more likely to report poor adherence compared with their counterparts. Interventions for patients using oral hypoglycemic agents, with lower expenditure, with irregular blood sugar monitoring, and which focus on better education and enhanced family support, are likely to enhance adherence in this population.