We investigate the determinants and extent of labor market discrimination toward people with acute physical disabilities (wheelchair users) using data from a large scale field experiment conducted in the province of Québec (Canada). Applications (cover letters and CVs) were randomly sent to 1477 private firms operating in two urban regions (Montréal and Québec City) advertising open positions requiring various skill levels. The applications were randomly generated to cover a broad spectrum of potential determinants of discrimination (gender, skill level, work history, workplace adjustment costs, etc.). We find that average callback rates of disabled and non-disabled applicants is 14.4% and 31%, respectively, yielding a differential callback rate of 46%. We also investigate whether the differential may result from accessibility constraints related to the physical infrastructures where firms are located (floor and access to an elevator, availability of wheelchair, etc.). The latter are found to have no explanatory power. In addition, applications which explicitly mention that the candidate is eligible to a government subsidy to cover the cost of workplace adaptations and assistive technology do not yield higher callback rates.