To evaluate the association between knee pain and lumbar disorders. The case-control study was conducted at Physical Medicine and Rehabilitation Department, Tabriz University of Medical Sciences, Iran, from December 2009 to March 2011, and comprised patients with primary complaint of knee pain. A separate group worked as controls. The coincidence of knee pain and lumbar disorders were assessed and compared between the two groups SPSS 15 was used for statistical analysis. Of the 170 patients, 90(53%) were in the case group having 20(22.2%) males and 70(77.7%) females, and 80(47%) in the control group having 18(22.5%) males and 62(77.5%) females. The overall mean age was 46.9±8.9 (range: 25-61years). Age and gender difference between two groups was not significant (p>0.05 each). Lifetime prevalence of radicular, chronic and recurrent low back pain and its point prevalence in the case group were significantly higher than the control group (p0.05). The relationship between lumbar and knee pain disorders should be considered in the assessment and management of patients with knee pain.