Introduction: Ultrasound guided axillary block is a widely used regional anaesthesia technique for upper limb surgery. Adding adjuvants to local anaesthetics can enhance block quality and prolong postoperative analgesia. This study aimed to compare onset time, duration of action, and analgesia within the first 24 postoperative hours between axillary blocks using clonidine versus dexamethasone as adjuvants. Patients and Methods: A descriptive and analytical prospective study was conducted over eight months. Patients were allocated into two groups according to the adjuvant used: clonidine or dexamethasone, combined with 0.5% ropivacaine. Outcomes included sensory and motor block onset, block duration, postoperative pain intensity, analgesic consumption, complications, and patient and surgeon satisfaction. Statistical analysis was performed using SPSS 26.0, with significance set at p < 0.05. Results: Among 109 patients undergoing upper limb surgery, 53 received an axillary block. Three were excluded, leaving 50 participants: 25 in the dexamethasone group and 25 in the clonidine group. The mean age was 43.6 ± 17.9 years, with a male predominance (76%). No statistically significant differences were found between groups regarding sensory or motor block onset, block duration, or postoperative analgesia (p > 0.05). No major complications occurred, and patient satisfaction was high. Conclusion: Ultrasound guided axillary block with either clonidine or dexamethasone as adjuvants is an effective and safe anaesthetic technique for upper limb surgery. No significant differences were observed between groups in block onset, duration, or postoperative analgesia.