Objective:To compare clinical effectiveness of Nickel Titanium (Ni-Ti) closed coil spring and active tiebacks during space closure in mandibular arch. To compare rate of anterior retraction by using Ni-Ti closed coil spring and active tiebacks in mandibular arch. To compare amount of anchor loss in mandibular arch with Ni-Ti closed coil spring and active tiebacks. Materials and Methods: A total of 20 patients with Class 1 bimaxillary proclination undergoing fixed orthodontic treatment (MBT 0.022 slot) after ?rst premolar extraction will be randomly selected from depatment of Orthodontics & Dentofacial Orthopaedics of K.D. Dental college, and will be divided into two groups for space closure. Patient will be informed about treatment and thesis procedure and consent regarding was taken. The space closure mechanics was allocated to the left or right side of same arch wire in each patient. Group 1 consisted of 10 patients in which right quadrant of maxillary arch, the space closure was done by Ni-Ti closed coil springs in 10 patients and by active ligature on left quadrant of the same 10 patients. Group 2 consisted of same 10 patients in which left quadrant of same arch, the space closure will be done by active ligature in 10 patients and by Ni-Ti closed coil springs on right quadrant of same 10 patients. The amount of anterior retraction, anchorage loss and rate of space closure was measured before start of retraction and patients will be called at six week interval for evaluation of retraction rate as T0, T1, T2, T3,T4. Results will be assessed on cast and Lateral Cephalogram were repeated at T4 for evaluation of anchorage loss. Result: Rate of anterior retraction and amount of anchorage loss was found to be slightly more with niti closed coil spring as compared to that of active tie back. Conclusion: NiTi closed coil springs achieved faster space closure as compared to the active tieback and significant amount of anchorage loss was also noted with NiTi closed