Introduction: Spinal anesthesia is commonly used in various surgical procedures, including hernia repair, different types of hysterectomy, cesarean section, prostate surgery, and urological bladder surgeries. Aim of the study: Our study aimed to assess urinary retention post-operative due to spinal anesthesia. Patients and methods: This prospective study was conducted at Imam Al-Hijjah Charitable Hospital, Karbala /Iraq from 5 January 2022 to 5 March 2022. Under the supervision of the Department of Anesthesia Technologies at Al-Mustaqbal University College – in Babil. After obtaining local ethics committee approval and written consent, 40 male patients only, aged 22–70 years, American Society Anesthesiologist – physical status I and II were divided into two types of anesthesia spinal (20) cases and general (20) cases undergoing surgery. Statistical Analysis: demographic data, including age, gender, type of surgery, time of surgery, type of anesthesia, drug anesthesia, and time of obstruction collected information were recorded using a checklist. Data were analyzed using IBM SPSS statistic version 20.0. Results of descriptive statistics were illustrated through frequency distribution tables and charts. Results: a decision is made to reject the null hypothesis and accept the alternative hypothesis Which proves that there is a significant difference with statistical significance between general and spinal at the time of obstruction this difference is due to the data with the higher average, as shown in the tables and graphs above. Discussion: the main finding in the present study is that postoperative urinary retention is common complication after general or spinal anesthesia. The incidence of postoperative urinary retention is affected by anesthetic technique. The bladder is composed of detrusor muscle and internal and external urethral sphincters. Conclusion: General anesthetics cause bladder atony by acting as smooth muscle relaxants and by interfering with autonomic regulation of detrusor tone. The patients were monitored after the operation for 2 - 2 and a half hours for elements of urinary tract obstruction. Recommendation: Based on the study, the following recommendations are suggested: A health education program about risk factors and complications of spinal anesthesia and ongoing research about how to decrease urinary retention after spinal anesthesia.