This study compared the different sling and resistance exercises on pelvic rotation during active straight leg raises (ASLR) and on pain in patients with chronic low back pain (CLBP). Methods: Twenty subjects were divided randomly into a sling group (SG) and a resistance exercise group (REG). Internal oblique (IO), external oblique (EO), rectus abdominis (RA), and rectus femoris (RF) muscle activity; pelvic rotation angle during ASLR; and visual analogue scale, pressure pain threshold were measured. Sling and resistance exercises were then performed for 30 minutes and the measurements taken again. Results: Both groups showed significantly lower RF muscle activity and significantly higher EO and IO muscle activity (p< 0.05). The RA muscle activity decreased significantly in the SG, but increased significantly in the REG (p< 0.05). The pelvic rotation angle was significantly lower in the SG (p< 0.05). The pain press threshold increased significantly in both groups (p< 0.05). The visual analogue scale decreased significantly in the SG (p< 0.05). Conclusion: Both exercises appear to be beneficial for modifying the muscle activity and pain control in the intervention of CLBP. On the other hand, the sling was more effective in increasing the pressure threshold than resistance exercise, and the pelvic rotation angle was reduced. Therefore, both exercises can help patients with CLBP change their muscle activity and control pain. CLBP patients should use a sling for short periods of time to learn to reduce the pain and control pelvic rotation.