Physical activity monitors can quantify various types of Physical Activities (PAs) in Manual Wheelchair Users (MWUs) with Spinal Cord Injury (SCI). The objective of this study was to develop new energy expenditure (EE) prediction models for MWUs with SCI based on an ActiGraph activity monitor. A total of 45 MWUs with SCI participated in this study and performed PAs including resting, wheelchair propulsion, arm-ergometry and deskwork activities. The EE models developed consisted of a general model for all activities combined and four activity-specific models. The EE estimation errors for the ActiGraph in the validation group (n=9) ranged from 16.7-42.1% for the general model and 15.4-25.0% for the activity-specific models. The EE estimated by general (r=0.88) and activity-specific (r=0.87) models significantly (P<0.05) correlated with the criterion EE. In conclusion, simple accelerometer-based activity monitors such as the ActiGraph can be used to quantify PAs in MWUs with SCI.