Testicular degeneration is a multifactorial process increasing the concentration of prostaglandins in seminal plasma. Both increase and decrease of these hormones tend to promote loss of seminal quality. Flunixin meglumine is a potent anti-inflammatory drug capable of modulating the production of prostaglandins and is widely used in female reproduction. However, it is rarely used in males with the same objective. Therefore, this study aimed to evaluate the effects of this drug on seminal quality of male lambs and goats with spermatic characteristics unfavorable for reproduction. To this end, a total of 15 breeding animals were evaluated, of which six goats and four sheep with poor seminal quality were selected according to the criteria established by the Brazilian College of Animal Reproduction (CBRA). Three semen samples were collected from each animal. Then, the flunixin meglumine treatment was initiated and ejaculates were collected at two different periods after the drug was administered (from day 21 until day 35 and from day 49 to day 63). Macroscopic and microscopic parameters were assessed in semen samples and scrotal circumference and percentages of sperm pathologies were measured and compared between the three periods. Data with normal distribution were analyzed using ANOVA at 5% probability, and comparisons between periods within the same species were performed using the Tukey test. An improvement was observed in the analyses of mass motility, percentage motility, and sperm vigor. Scrotal circumference had no variation. Concerning sperm pathologies, an increase in the number of normal spermatozoids was observed due to a significant reduction in minor and major defects, and the latter remained low even after the treatment was finished. Therefore, flunixin meglumine presented beneficial effects on seminal parameters of male goats and lamb with unfavorable spermatic characteristics. These findings indicate this drug may be used in the treating of males with testicular injuries or of breeders with reduced seminal quality due to advanced age.