Introduction: Not many risk factor studies for low back pain have been done in Sri Lanka. Objectives: To determine the association between low back pain and posture, exercise, family history, level of education, level of income, smoking, consumption of alcohol, body mass index (BMI) and consumption of animal proteins. Methodology: A case control study was done at two main teaching hospitals in Colombo North region Sri Lanka. This study was done on adult subjects. A pretested structured interviewer administered questionnaire was used to collect data. Their weights and heights were also measured. Results: The data were collected from 530 cases and 530 controls. Their age range was 18- 90 years. Mean age (SD) for cases was 49.4 (15) years. Mean age (SD) for controls was 47.1 (17) years. Females accounted for 67% of cases and 64% of controls. Bad posture (P < 0.001), low level of physical exercise (P < 0.001), positive family history (P < 0.001), high level of income (P < 0.001), high BMI and low BMI (P = 0.001), low level of education (P = 0.013) and regular consumption of alcohol (P = 0.039) had a significant association with low back pain. Smoking and consumption of animal proteins did not have a significant association with low back pain. Conclusion: Posture, exercise, family history, level of education, consumption of alcohol, level of income and BMI had a significant association with low back pain. Being overweight and underweight were both risk factors for low back pain