Abstract: Background-Various prognostic factors in assisted reproduction procedures have been described and analysed, including woman’s age, the cause of infertility, the ovarian response and uterine receptivity, the semen quality, and the BMI. Optimal BMI is required for an optimal response.There is controversy among various reports, which is partly caused by the varying focus of investigators and differences in study designs, led us to examine the relationship between BMI and IVF/ICS1 outcome in our unit. OBJECTIVE: To study impact of BMI on IVF outcome prospectively. MATERIAL/METHODS: It Prospective study over a period of 1 year in the age group 25-35 years attending the IVF clinic was conducted at a tertiary infertility centre in Bangalore, India between November 2010-October 2011. RESULTS: There was close association of increased BMl in particular when BMl is > 30 kg/m2 and the reduced outcomes of IVF/ICSI treatment in the form of less clinical pregnancy and higher early pregnancy loss. Furthermore, increased BMl was related to an increased FSH requirement, longer days of stimulation, higher dosage of gonadotropins, increased risk of cancellation and fewer collected oocytes. CONCLUSIONS: Obesity is associated with an increased risk of early pregnancy loss. Also need of high dose of gonadotropin ,less number of collected oocytes is observed. Implantation rate ,pregnancy rate and miscarriage rate was comparable but live births are high in normal weight and overweight as compared to extremes of BMI due to high number of miscarriages in extremes of BMI though not statistically significant.So will be appropriate to recommend weight loss prior to IVF.