Optimal neoadjuvant hormone therapy (NHT) for reducing prostate cancer (PC) patients' prostate volume pre-brachytherapy is controversial. We evaluated the differential impact of neoadjuvant gonadotropin-releasing hormone (GnRH) antagonist versus agonist on post-brachytherapy testosterone recovery in 112 patients treated pre-brachytherapy with NHT (GnRH antagonist, n=32; GnRH agonists, n=80) (Jan. 2007-June 2019). We assessed the effects of patient characteristics and a GnRH analogue on testosterone recovery with logistic regression and a propensity score analysis (PSA). There was no significant difference in the rate of testosterone recovery to normal levels (> 300 ng/dL) between the GnRH antagonist and agonists (p=0.07). The GnRH agonists induced a significantly more rapid testosterone recovery rate at 3 months post-brachytherapy versus the GnRH antagonist (p<0.0001); there was no difference in testosterone recovery at 12 months between the GnRH antagonist/agonists (p=0.8). In the multivariate analysis, no actor was associated with testosterone recovery. In the PSA, older age and higher body mass index (BMI) were significantly associated with longer testosterone recovery. Post-brachytherapy testosterone recovery was quicker with the neoadjuvant GnRH agonists than the antagonist, and the testosterone recovery rate was significantly associated with older age and higher BMI. Long-term follow-ups are needed to determine any differential effects of GnRH analogues on the quality of life of brachytherapy-treated PC patients.