The prognostic value of inflammatory indices such as absolute monocyte count (AMC) has been a subject of interest in recent prostate cancer (PCa) literature, while hemoglobin concentration (HGB) has been recognized as a survival factor in castration-resistant metastatic prostate cancer, but its value remains unclear in localized disease. The aim of this study was to test the prognostic value of these two simple and inexpensive biomarkers for survival based on a cohort of 1016 patients treated with primary radiotherapy and androgen deprivation therapy for localized or locally advanced intermediate- or high-risk PCa. Complete survival data was available for all cases based on the National Cancer Registry with a median observation time of 120 months (IQR 80.9-144.7). Missing blood test data were supplemented using the Nearest Neighbor Imputation, and the Cox proportional hazards regression model was used for analysis. The median age was 68.8 years (IQR 63.3-73.5). The five-year overall survival was 82.8%, and 508 patients were alive at the time of analysis. The median time between blood tests and the first day of radiotherapy was 6 days (IQR 0-19). HGB (p = 0.009) and AMC (p = 0.003) were independent prognostic factors for survival, along with age, ISUP Grade Group, clinical T stage and maximum PSA concentration. The study demonstrated that HGB and AMC can be useful biomarkers for overall survival in patients treated with radiotherapy for localized intermediate- or high-risk PCa.