OBJECTIVE Corticosteroid injections can provide (temporary) relief in patients with mild to moderate carpal tunnel syndrome (CTS). Hydrodissection as part of an injection has been associated with positive clinical outcomes but data for CTS so far has been scarce. This study is designed to assess patient tolerance and secondarily provide pilot data on the added effect of hydrodissection. METHODS Twenty CTS patients were randomized to an ultrasound-guided betamethasone injection with hydrodissection (5 mL) or without (2 mL). Patient tolerance was assessed directly after intervention and patient-reported outcome after 4 and 24 weeks. Intra-group data were compared using Wilcoxon Signed Rank and inter-group with Wilcoxon rank-sum tests. RESULTS Tolerance and pain scores did not differ between the two groups. Symptom scores decreased in both groups, but to a lesser extent in the hydrodissection group with a mean difference of -0.8 versus -1.5 in the control group at 4 weeks (P = .02). At 6 months, this difference was no longer present (P = .81). No statistically significant differences were found between the hydrodissection and control groups in the function or pain scores at follow-up at either time point. CONCLUSIONS After injection, both symptomatic and functional scores improved, but the hydrodissected group did not show additional improvement. Data presented can be used to support larger studies to assess the value of hydrodissection in CTS management.