Long's manipulation (LM) is a representative Chinese manipulation approach incorporating both spinal manipulation and traditional Chinese massage (TCM) techniques. This randomized controlled trial (RCT) aimed to compare the immediate and short-term relative effectiveness of LM to TCM on patients with chronic neck pain. Patients were randomly assigned to either LM group or TCM group. LM group was treated with Long's manipulation, while the TCM group received TCM therapy. Patients attended 8 sessions of treatment (one session every three days). Outcome measures included neck disability (Northwick Park Neck Pain Questionnaire; NPQ), pain intensity (Numeric Pain Rating Scale; NPRS), patient perceived satisfaction of care (PPS) (11-point scale), craniovertebral angle (CV angle) and cervical range of motion (ROM). A blinded assessor performed assessment at baseline, immediate after treatment and 3 months post treatment. LM group achieved significantly greater improvement than TCM group in pain intensity (p < 0.001), neck disability (p = 0.049) and satisfaction (p < 0.001) up to 3-month follow-up. There was no significant difference in improvements in CV angle and most of cervical ROM between groups (p = 0.169 ∼ 0.888) with an exception of flexion at 3-month follow-up (p = 0.005). This study shows that LM could produce better effects than TCM in relieving pain and improving disability in the management of patients with chronic mechanical neck pain.