Background Ultrasound-guided needle biopsy (USGNB) allows for precise and immediate viewing of pleural lesions, effusions, and needle placement without ionizing radiation. This study aimed to assess the efficacy of US-guided tru-cut needle pleural biopsy in diagnosing unexplained exudative pleural effusion compared to medical thoracoscopy (MT), focusing on safety, accuracy, time, and cost of the treatment. Patients and methods This observational cross-sectional research was conducted on 40 patients over 18 years old, of both sexes, with unexplained exudative pleural effusion. The patients were randomly separated into two equal groups. The girst group is USGNB and the second group is MT. Results Group II exhibited substantially greater costs, sedation levels, procedure duration, biopsy site discomfort, surgical emphysema, lung expansion failure, and psychological distress compared to group I (P<0.05). There was no notable disparity between the two groups regarding radiological detection of pleural effusion, pleural fluid properties, procedural observations, histological results, and diagnostic effectiveness. The duration of hospitalization was considerably shorter in group I compared to group II, assessed from the day of the operation to the day of release (P=0.001). Conclusion USGNB is an important tool in the diagnosis of pleural effusion after failure of pleural fluid analysis, which is performed by a chest physician is an accurate, safer, lower in cost, and shorter in duration with fewer complications compared with MT.