Access to prescription-type substances in the workplace is a unique feature of the practice of health professionals. Empirical data on the relation between workplace access to substances and prescription-type drug misuse among nurses are limited. Using an anonymous mailed survey, data were collected on three dimensions of access: perceived availability, frequency of administration, and degree of workplace control over storage and dispensing of substances. Each dimension was independently associated with increased use. When these dimensions were combined into an index, nurses with very easy access were most likely to have misused prescription-type drugs (adjusted Odds Ratio = 4.18; 95% Confidence Interval: 1.70-10.30). Level of knowledge of controlled substances was also associated with use, but did not explain the relation between access and use.