Dissertation (MMED General Surgery)Background: Benign prostate hypertrophy (BPH) is a prostatic enlargement associated with the presence of voiding symptoms and/or histological evidence of hyperplasia on biopsy. Trans urethral resection of prostate (TURP) is considered as the gold standard management for BPH. Despite being one of the common urological procedures in Tanzania, complications of TURP have not been well explored. There was limited published information on the incidence and prevalence of Benign Prostate Hypertrophy and lower urinary symptoms. So it was essential to see the complications we get so that some changes may be made. Objectives: The study aimed at determining post TURP serum electrolytes changes among operated cases at Benjamin Mkapa Hospital. Specifically to determine serum electrolyte before TURP, serum electrolyte changes caused by TURP and factors associated with serum electrolyte changes during TURP. Methodology: A prospective cross-sectional study that was conducted in the Urological Department at Benjamin Mkapa Hospital from December 2019 to February 2020. All in patients undergoing TURP admitted in urology wards at Benjamin Mkapa Hospital were enrolled for the study. Descriptive, t test and logistics regression were used in analysis. Results: The study involved 85 BPH patients with mean ageof 68.2 years ±9.84. About64% had at least one co-morbidity. The most common comorbidity was Hypertensive Heart Diseases 17%. About 31 (36%) had serum electrolyte imbalances before TURP in which 12 (38.7%) had hypernatremia with mean serum sodium level of 147.604±1.735. The total of 24 (28.2%) of all patients who underwent TURP had different electrolyte imbalances in which hypernatremia (148.12±3.143) was the common imbalance 12 (50%) patients. Statistically there was no significant change of serum electrolyte after TURP. The significance predictors of electrolyte changes were age of the patients and irrigation Fluid with the P - values of 0.04 and 0.004 respectively. Conclusion and recommendations Some of the patients had electrolyte imbalances preoperatively. There were no significant electrolyte changes after TURP in this study. Age and irrigation fluid were significant factors for electrolyte changes in TURP. There should be thorough preoperative investigations of the preoperative patients, specially prepared for the TURP.To use the minimum amount of fluid used in irrigation in order to void electrolyte imbalance.