The widely varied regulations in the 50 states often limit consumer access to nurse practitioners (NPs). In 22 states, the Board of Nursing (BON) must share NP regulatory authority with another profession, usually physicians. This study examines the relationship between the BON as the sole authority regulating NPs or sharing that authority with another profession and the NP regulatory environment. Independent t tests compared the NP regulatory environments for consumer access and choice in states with sole BON regulation with those in states with involvement of another profession. The states' NP regulatory environments were quantified with an 11-measure tool assessing domains of consumer access to NPs, NP patients' access to service, and NP patients' access to prescription medications. BON-regulated states were less restrictive (P < .01, effect size 1.02) and supported NP professional autonomy. Entry into practice regulations did not differ in the two groups of states. Having another profession involved in regulation correlates with more restrictions on consumer access to NPs and more restrictions to the full deployment of NPs. © 2010 Elsevier Inc. All rights reserved.