Background: Regional anesthesia can provide superior pain management and perhaps improve patient outcomes. Ultrasound guidance may be associated with better results of regional anesthesia block. Objective: Detection of the important differences between conventional and ultrasound guided interscalene block. Patients and methods: Following approval to enter the study and obtaining informed consents from the patients, sixty patients who scheduled for upper limb surgery were randomized into two equal groups: ● Group A: conventional interscalene brachial plexus block (ISBPB) using conventional landmark-guided interscalene block. ● Group B: Ultrasound-guided interscalene brachial plexus blockguided by two dimensional ultrasonic images. Results: Both groups were comparable as regard to patient demographics, surgical intervention and premedication. Ultrasound guided group had shorter time to detect the plexus, injection of local anesthesia, and shorter time of sensory blockage. However, the difference was statistically non-significant. On the other hand, ultrasound guided group had the advantages of significantly shorter time to reach motor blockade, and significant longer duration of both sensory and motor block. Finally, success rate was high in ultrasound guided group, but the difference was statistically non-significant. Conclusion: Conventional and Ultrasound-guided guidance provided comparable sensory block onset times, complications, and success rates in patients undergoing interscalene block. Ultrasound guided block showed significantly shorter time to reach motor blockade and significant longer duration of both sensory and motor block.