The study examined the associations between dietary and lifestyle factors and risk of non-Hodgkin's lymphoma (NHL) in Oman. Forty three histologically confirmed NHL cases diagnosed at Sultan Qaboos University Hospital (SQUH) and Royal Hospital, Muscat, Oman and their forty three age matched controls were used in this case control study. A frequency matching was used in selecting the population based controls to achieve similar age and sex distribution to that of all cancer cases. Dietary intake information was collected in personal interviews with cases and control subjects, using a 117-item semi-quantitative food frequency questionnaire. The statistical analysis of the data was conducted using the odds ratios (OR) and 95% confidence intervals (95% CI), calculated from the maximum likelihood estimates using the binary logistic regression. A non-significant increased risk of NHL was observed with higher body mass index (BMI) (OR= 1.20, 95% CI: 0.45, 2.93), whereas a significantly decreased NHL risk was observed to be associated with higher educational level of respondents (OR=0.12, 95% CI: 0.03, 0.53). When the highest quartile of intake was compared with the lowest, a significantly increased risk was observed for higher intake of energy (OR= 2.67, 95% CI: 0.94, 7.57), protein (OR= 1.49, 95% CI: 0.54, 4.10) and carbohydrate (OR= 5.32, 95% CI: 1.78, 15.86). Higher consumption of daily servings from cereals (OR=3.25, 95% CI: 0.87, 12.09) and meat groups (OR= 1.55, 95% CI: 0.58, 4.15) were found to be associated with NHL risk, whereas a significantly reduced risk was associated with higher consumption of vegetables (OR= 0.24, 95% CI: 0.07, 0.82). The consumption of fruits and milk however did not show any significant association with NHL risk. No apparent association was observed between the fat intake and percentage contribution of energy from various macronutrients with NHL risk. Overall, the results of the present study suggested that diet has an association with NHL risk.