Skin is the largest organ and outer covering of human body. It plays a great role in our visible appearance. Humans are more conscious about skin disease because it has a cosmetic priority. The cases that fulfil the selection criteria will be enrolled as study samples with a view to see correlation with glycosylated Hb, vascular changes and duration of DM. This cross-sectional study was performed in the Department of Skin and VD and the Department of Pathology of BIRDEM, Dhaka, Bangladesh from March 2017 to February 2019. Study population was all diabetic patients with skin diseases attending dermatology department of BIRDEM hospital. Among them 90 patients were selected who will do skin biopsy with diabetes mellitus. Skin biopsy tissue and blood sample were taken as materials to determine the type of skin lesion in patients with satisfactory and unsatisfactory glycaemic control; the relationship of diabetic skin lesions with duration of diabetes; and assessing the cutaneous or dermal capillary vascular changes was in Diabetes Mellitus and its correlation with HbA1c level and duration of Diabetes Mellitus. Among 90 cases age ranged from 31 to 85 years with mean age of the patients 55.06 ± 12.10 years. Maximum patients were in age group 41-50 years (32.2%). Skin disorders in Diabetes mellitus are more common in female in this study. Almost three fourth of the patients glycemic status was unsatisfactory. Satisfactory glycemic patients were 17 cases (18.9%) and unsatisfactory glycemic patients were 73 cases (81.1%). Mean HbA1c shows unsatisfactory glycemic status among 90 cases in this study. Mean HbA1c is more unsatisfactory in female patients in this study. Most common group of lesion was 37.7 % belong to miscellaneous group followed by skin diseases with strong to weak association with DM. There were no significant differences in different types of skin lesions between satisfactory and unsatisfactory blood glucose patients. Majority of the cases (37.8%) occurred after 10 years of diagnosis of DM. Mean duration of DM was highest among the patients with skin reaction to diabetic treatment (10.04±6.19). There is marked variation in thickness of dermal capillary basement membrane with duration of diabetes. There was a significant inverse correlation between perivascular infiltration and capillary basement membrane thickness.