Introduction. Spasticity occurs in disorders of the central nervous system such as stroke, spinal cord injury (SCI), multiple sclerosis and traumatic brain injury. The recently developed clinical measurement for the measurement of spasticity is the Modified Modified Ashworth Scale (MMAS) Purpose of study. The purpose of this study is to determine the inter-rater reliability of the MMAS in the assessment of plantar flexor spasticity in patients with SCI. Methodology. Thirty-eight subjects (32 males and six females, mean age 31.9 +/- 12.6 years) were recruited for the study. Excluded from the study were patients with contracture in the lower limb and where passive movements were contraindicated. Procedure. Each patient was assessed by two raters in a single session. After the performance of the procedure by the first assessor and rating of the patient's muscle tone with the MMAS, the same procedure was repeated by the second assessor after 1 hour. The evaluation was carried out in side-lying position. The extent of agreement was analysed by non-weighted Cohen kappa. Results. The agreement between the raters was good (soleus -: 0.75, SE = 0.084, p < 0.0001, gastrocnemius -: 0.70, SE = 0.105, p < 0.0001). Conclusion. The MMAS has good inter-rater reliability in the assessment of plantar flexor muscle spasticity in patients with SCI. Copyright (C) 2014 John Wiley & Sons, Ltd.