The objective of this study was to evaluate inflammatory markers as predictors of fertility after varicocelectomy and to develop a prediction model. This prospective cohort was conducted on patients with varicoceles who were presented to the clinic of Imam Reza hospital of Tehran during 2019-2020. Semen analysis, complete blood count (CBC), and scrotal ultrasonography was requested. Patients with abnormalities of semen analysis were chosen as candidates for varicocelectomy. 6 months after the operation, semen analysis was repeated. Hematologic and semen analysis parameters were recorded at baseline and follow-up visits. Treatment success was defined as 50% increase in total motile sperm count (TMSC) in cases with preoperative TMSC> 5 million/cc or 100% increase in TMSC in cases with preoperative TMSC< 5 million/cc. Patients were then categorized into two groups based on treatment success and statistical analysis was performed on these two groups. 124 infertile patients with varicocele were evaluated in our study. 52 patients (41.93%) showed improvements in semen analysis after varicocelectomy. After univariate and multivariate analysis three parameters were used in our predictive model as body mass index (BMI)>23.70 kg/m2 (4 scores), neutrophil-lymphocyte ratio (NLR) >1.80 (3 scores), and TMSC<14.69 million (2 scores). A cut-off value of 5 was associated with an 87.5% sensitivity and an 84.6% specificity for the prediction of failure of varicocelectomy. Varicocelectomy can improve semen analysis parameters in almost all infertile men with varicocele. Using BMI, NLR, and baseline TMSC as the suggested scoring system can predict the success of varicocelectomy for improving fertility and determine the appropriate infertile candidates for surgery.