Although weakness of anterior cervical muscles is postulated to contribute to persistent neck pain in patients with mechanical neck pain, quantitation of weakness has never been reported. We compared anterior cervical muscle strength in 30 subjects with mechanical neck pain and in 30 asymptomatic control subjects. Testing was performed with the subject supine, chin retracted, and neck flexed. Assessment was made using a hand-held dynamometer with head held at the midline and with rotation left and right within a pain-free range. Analysis with Wilcoxon scores showed that patients with neck pain had significantly less (p less than .05) strength (N.Kg-1) in all three positions than controls (1.16 +/- 0.49 vs 1.71 +/- 0.42, sagittally; 1.01 +/- 0.52 vs 1.47 +/- 0.41, rotation left; .99 +/- 0.46 vs 1.43 +/- 0.43 rotation right; neck pain vs control, respectively.) This weakness and its role in persistent neck pain should be recognized. The efficiency and effect of cervical muscle strengthening in treatment of chronic neck pain should be further defined.