In many Western countries, hospital emergency departments are overcrowded, leading to the desire to strengthen primary care, particularly after hours. To achieve this goal, an increasing number of Western nations are reorganizing their after-hours primary care systems into large-scale primary care physician (PCP) cooperatives. This article provides an overview of the organization, performance, and development of PCP cooperatives in the Netherlands. The Dutch after-hours primary care system might offer opportunities for other countries facing problems with after-hours care and inappropriate emergency department visits. During the past several years, the number of contacts with Dutch PCP cooperatives has increased to 245 contacts per 1000 citizens per year. Many contacts (45%) are nonurgent, and about half occur as part of a series of primary care contacts. Low accessibility and availability of daytime primary care are related to greater use of after-hours primary care. To prevent unnecessary attendance at the cooperatives, physicians advocate copayment, a stricter triage system, and a larger role for telephone doctors. More than half of the PCP cooperatives in the Netherlands have integrated with hospital emergency departments, forming "emergency care access points." This collaboration has decreased emergency department use by 13% to 22%, and treatment of self-referrals by PCP cooperatives in emergency care access points is safe and cost-effective. Direct access to diagnostic facilities may optimize efficiency even more. Other recent developments include access to electronic health records of daytime primary care practices, task substitution from physicians to nurses, and the launch of a 2-year training program for PCPs to become experts in emergency care.