Background and Introduction: Core muscle strengthening and behavioural therapy are the two main treatment strategies employed in the management of chronic non specific low back pain in nursing population. But there is very little evidence about the effect of a combined treatment protocol of core muscle strengthening and behavioural therapy in the management of chronic non specific low back pain. Objectives : To determine the effect of core muscle strengthening and behavioral therapy separately and in combination on pain, disability and fear avoidance beliefs in nurses with chronic non specific low back pain. Methods: According to the inclusion and exclusion criteria, 45 nurses who were evaluated for chronic non specific low back pain were enrolled in the study. 15 nurses each were allocated to core muscle strengthening group, behavioral therapy group and the combined group. Outcome measures used were Visual analogue scale, Rolland Morris Disability Questionnaire and Fear Avoidance and Belief Questionnaire. Base line data was collected initially and then post treatment data was taken after two weeks. Results : Intra group comparison of all the outcome measures using paired sample statistics showed significant difference in the pre and post treatment evaluation (p<0.005). In overall inter group comparison using ANOVA significant differences for all three groups were evident (p<0.005). Multiple Scheffe test showed that the combined treatment group showed larger differences than others in most of the outcome measures. Conclusion : These findings suggests that combined treatment protocol induced greater improvement in pain, disability and fear avoidance beliefs than when core muscle strengthening and behavioral therapy was administered alone.