BACKGROUND: The relationship between psychiatric consultation and antipsychotic prescribing in nursing homes (NH) is unknown. OBJECTIVE: To identify the association between psychiatric consultant groups and NH-level antipsychotic prescribing after adjustment for resident case-mix and facility characteristics. RESEARCH DESIGN AND SUBJECTS: Nested cross-sectional study of 60 NHs in a cluster randomized trial. We linked facility leadership surveys to October 2009-September 2010 Minimum Data Set, Nursing Home Compare, the US Census, and pharmacy dispensing data. MEASURES: The main exposure is the psychiatric consultant group and the main outcome is NH-level prevalence of atypical antipsychotic use. We calculated annual means and interquartile ranges of NH-level antipsychotic use for each consultant group and arrayed consultant groups from lowest to highest prevalence. Generalized linear models were used to predict antipsychotic prescribing adjusting for resident case-mix and facility characteristics. Observed versus predicted antipsychotic prescribing levels were compared for each consultant group. RESULTS: Seven psychiatric consultant groups served a range of 3-27 study facilities. Overall mean facility-level antipsychotic prescribing was 19.2%. Mean prevalence of antipsychotic prescribing ranged from 12.2% (SD, 5.8) in the lowest consultant group to 26.4% (SD, 3.6) in the highest group. All facilities served by the highest-ranked consultant group had observed antipsychotic levels exceeding the overall study mean with half exceeding predictions for on-label indications, whereas most facilities served by the lowest-ranked consultant group had observed levels below the overall study and predicted means. CONCLUSIONS: Preliminary evidence suggests that psychiatric consultant groups affect NH antipsychotic prescribing independent of resident case-mix and facility characteristics.