Background: Men suffering from premature ejaculation often report emotional and relational problems, and some of them do not pursue sex due to embarrassment. This condition leads to mental disorders, e.g., anxiety and depression, and the couple's relationship may suffer. Objectives: The present study aimed to investigate the effectiveness of transcranial direct-current stimulation (tDCS) and behavior therapy using the start-stop method in improving premature ejaculation. Methods: This was a quasi-experimental study with two experimental groups and a control group. The statistical population comprised all men with premature ejaculation residing in Tehran (2021) who visited sexual health centers in this city. A sample of 45 men aged 25-65 was selected using convenience sampling and divided into three groups of 15. The research instrument included the International Index of Erectile Function (IIEF). The data were analyzed in SPSS-23 using the analysis of covariance. Results: The mean ± SD of the pretest of premature ejaculation in the tDCS, start-stop method, and control groups was 13.60 ± 5.45, 12.86 ± 3.24, and 15.68 ± 4.87, respectively; while in the posttest was 23.53 ± 9.65, 18.66 ± 5.25 and 17.53 ± 4.83, respectively. Based on the results, tDCS alleviated premature ejaculation (P < 0.001). The start-stop method also decreased the symptoms of premature ejaculation, but this reduction was not significant. There was a significant difference between the two treatment methods, and tDCS proved more effective. Conclusions: tDCS demonstrated acceptable effectiveness in the treatment of premature ejaculation. Given its effectiveness in increasing marital satisfaction, it should be considered in the treatment of premature ejaculation.