Periodontal disease (PD), a chronic inflammatory condition characterized by destruction of the supporting tissues of the teeth, increases the risk of complications in diabetics. Diabetic retinopathy (DR) is a microvascular complication of prolonged hyperglycaemia. There appears to be a similarity in the pathogenesis of DR and PD. Hence, this study aimed to investigate the association, if any, between DR and PD, correlate the severity of DR with the severity of PD, and investigate the association between glycated haemoglobin (HbA1c), serum creatinine and periodontal variables. The periodontal status of 200 adult diabetic patients in the age group of 30–65 years with varying severity of DR was assessed. Evaluation of the severity of PD was assessed by recording clinical parameters. Haematological investigations including glycated haemoglobin (HbA1c) and serum creatinine were estimated before the initiation of treatment for DR. A statistically significant association between the mean duration of diabetes mellitus (DM) and the severity of DR and PD was found. The severity of PD was directly correlated with the severity of DR. There was a significant association between the levels of HbA1c and serum creatinine and severity of DR and PD. There could be a plausible relationship between DR and PD. Further prospective studies on a larger population with longer follow-ups are required to ascertain whether PD and its severity directly affect the progression and severity of DR.