The objective of this study is to determine the efficacy of stanozolol in the treatment of tracheal collapse (TC) in dogs, which is the analogous disease to tracheomalacia (TM) in humans. Twenty-two dogs with endoscopically confirmed and graded TC were enrolled into five groups. Groups S1 (n=5), S2 (n=5) and S3 (n=4) with grade 1, 2 and 3 TC, respectively, received stanozolol orally for 75 days, while groups P1 (n=4) and P2 (n=4) with grade 1 and 2 TC, respectively, received placebo. The clinical score was evaluated every 15 days, whereas TC grade was reassessed at the end of the experiment. Clinical improvement was detected from the 30th day in S2 and S3 group dogs and from the 45th day in S1 group dogs and continued until the end of the experiment. Also, statistically significant differences were seen between S2 and P2 dogs from the 30th day, and between S1 and P1 dogs from the 60th day, and continued until the end of the study. Amelioration of the TC grade was seen in 13 of 14 (92.9%) dogs, which received stanozolol. Of the 14 dogs, 57.1% were cured and 35.8% demonstrated a less severe TC grade, while only one dog (7.1%) did not improve at all. Stanozolol seems to be an effective drug in the management of canine TC and it may have potential for use in humans with TM.