Background: Obesity and migraine are the most common disorders among general population that are linked with disability and impaired life quality. Though, several studies have investigated the relationship between obesity and migraine but yet there is no complete knowledge regarding association between BMI and migraine, particularly chronic migraine. Objective: The objective of the study was to find the association between body mass index and migraine. Material and Methods: It was a prospective study carried out at Neurology Outpatient Department of Lahore General Hospital, Lahore. Total of 545 patients with major complaint of headache were included after fulfilling “episodic migraine” (n=370) and “chronic migraine” (n=175) criteria according to International Headache Society (IHS) criteria. Results: Among 370 patients with episodic migraine (EM), 78.4% were females while among 175 patients with chronic migraine (CM), 81.1% were females. In EM group, the mean age of the patients was 41.72+21.35 years and in CM group, it was 45.80+15.79 years. In EM group, mean pain intensity was 4.6+2.41 and in CM group, mean pain intensity was 4.3+2.51. Among EM group patients, mean duration of headache was 4.85+5.17 days and among CM group patients, mean duration was 20.88+8.86 days. Mean BMI (Body Mass Index) of patients in EM groups was 22.91+3.89 while in CM groups was 24.43+3.43 (P=0.002). In EM group, 9.7% patients and in CM group, 6.3% patients were underweight (P=0.189). In EM group, 11.4% patients and in CM group, 30.3% patients were overweight (P=0.002). However, in EM group, only 1.3% patients and in CM group, 3.4% patients were obese (P=0.087). Multiple logistic regression analysis of chronic migraine group showed significant results (P <0.05) regarding headache days/month, BMI, overweight and obese. Conclusion: Study concluded that overweight and obesity were associated factors for migraine. Chronic migraine patients were more likely to have elevated BMI than the episodic migraine patients. Keywords: Body mass index, migraine, obesity, chronic, headache