The need to include simultaneous carpal tunnel release (sCTR) with forearm fasciotomy for acute compartment syndrome (ACS) or after vascular repair is unclear. We hypothesized that sCTR is more common when: 1) fasciotomies are performed by orthopedic or plastic surgeons, rather than general or vascular surgeons; 2) ACS occurred because of crush, blunt trauma, or fractures rather than vascular/reperfusion injuries; 3) elevated compartment pressures were documented. We also sought to determine the incidence of delayed CTR when not performed simultaneously. Retrospective chart review identified patients who underwent forearm fasciotomy for ACS or vascular injury over a period of 10 years. Patient demographics, mechanism of ACS or indication for fasciotomy, surgeon subspecialty, compartment pressure measurements, inclusion of sCTR, complications, reoperations, and timing and method of definitive closure were analyzed. Logistic regression modeling was used to analyze predictors associated with delayed CTR. Fasciotomies were performed in 166 patients by orthopedic (63%), plastic (28%), and general/vascular (9%) surgeons. Orthopedic and plastic surgeons more frequently performed sCTR (67% and 63%, respectively). A total of 107 (65%) patients had sCTR. Fasciotomies for vascular/reperfusion injury were more likely to include sCTR (44%) compared with other mechanisms. If not performed simultaneously, 11 (19%) required delayed CTR at a median of 42 days. ACS secondary to fracture had the highest rate of delayed CTR (35%), and the necessity of late CTR for fractures was not supported by the logistic regression model. Residual hand paresthesias were less frequent in the sCTR group (6.5% vs 20%). Overall complication rates were similar in both groups (63% sCTR vs 70% without sCTR). When sCTR is excluded during forearm fasciotomy, 19% of patients required delayed CTR. This rate was higher (35%) when ACS was associated with fractures. Simultaneous CTR with forearm fasciotomy may decrease the incidence of residual hand paresthesias and the need for a delayed CTR. Prognosis IV.