Objective: To assess whether mental imagery of gripping prevents the loss of grip strength associated with forearm immobilization. Design: Pretest–posttest randomized-group design. Setting: Laboratory. Participants: 13 female and 5 male university students, age between 17 and 30 years, randomly assigned into 2 groups—1 control and 1 experimental. Interventions: Both groups had their nondominant forearms immobilized for 10 days. The experimental group undertook three 5-min mental-imagery sessions daily, during which they imagined they were squeezing a rubber ball. Main Outcome Measures: Wrist-flexion and -extension and grip strength before and after immobilization. Results: There was no significant change in wrist-flexion or -extension strength in the mental-imagery group. The control group experienced a significant decrease in wrist-flexion and -extension strength during the period of immobilization (P < .05). Conclusions: Despite study limitations, the results suggest that mental imagery might be useful in preventing the strength loss associated with short-term muscle immobilization.