ObjectiveTo compare the effectiveness of Proprioceptive Neuromuscular Facilitation (PNF) and Passive Vertebral Mobilization (PVM), both when given in adjunct to routine physical therapy (RPT), on neck disability in patients with mechanical neck pain (MNP). MethodsA single-blinded randomized controlled trial was conducted on 90 patients with MNP at the National Institute of Rehabilitation Medicine, Islamabad, Pakistan, from September 2015 to March 2018. The participants aged between 18 and 65 years were recruited through a simple random sampling technique and randomly divided into three groups i.e. PNF + RPT, PVM + RPT, and RPT. Each participant was evaluated pre and post-intervention (after four weeks) through neck disability index (NDI). The data were analyzed by using SPSS version 21. ResultsThe MANOVA was run on the pre-post mean differences of the variables to determine the changes within the groups which showed that the participants improved significantly in all the groups in terms of the NDI components and overall NDI score (p < 0.05). Univariate analysis with the post-hoc comparison and Tuckey HSD correction was used to determine the differences between the groups which showed that there was a significant difference between the interventional groups in the overall pain intensity, as well as pain experienced while performing personal care activities, reading, doing work, driving, sleeping, recreation and in the total NDI score (p < 0.05). ConclusionPVM (in adjunct to RPT) was more effective than PNF (in adjunct to RPT) for the patients with MNP to manage themselves in daily activities. Clinical trial registrationNCT03813680 (at clinicaltrials.gov) (https://clinicaltrials.gov/ct2/show/NCT03813680)