This was a study to assess the prevalence of carbohydrate intolerance of varying degrees in pregnant females registered at a tertiary care hospital in western India. Prospective screening of pregnant females was carried out (2005-2007) with oral glucose tolerance test (OGTT) based on American Diabetes Association (ADA) 2005 criteria. One thousand two hundred and twenty-five women with mean age 25.4 years (18-40) of which average risk and high risk were found in 408 (33.3%) and 817 (66.7%) cases respectively. Gestational diabetes mellitus (GDM) was diagnosed in 94 cases (7.7%) while 171(13.9%) had impaired gestational glucose tolerance (IGGT) ie, one value abnormal on 3-hour OGTT, while the combined prevalence of GDM and IGGT was 21.6% (n=265). Prevalence of GDM and IGGT was more in patients with age more than 30 years compared to younger females [GDM: 17.6% versus 6.8% (p=0.00); IGGT : 21% versus 13.4% (p=0.00)]; and in those with body mass index (BMI) >23 compared to BMI<23[GDM: 11.4% versus 8.3% (p=0.0374); IGGT : 22.8% versus 10.5 % (p= 0.0028)]. As the maternal age [odd's ratio {OR} :1.32; confidence interval {CI} (1.20 - 1.55) (p=0.000)] and prepregnancy BMI [OR:1.43; CI (0.65 - 3.14), (p=0.0316)] increases; prevalence of GDM, IGGT increased. There was a non-significant trend of increased GDM and IGGT in patients with family history of diabetes, bad obstetric history, history of macrosomic baby and decreased physical activity. So it is concluded GDM and IGGT affects one-fifth of pregnant females from western India on selective screening with increasing maternal age and BMI being significant risk factors associated.