Summary The development of mutual and commercial health insurance, and state health insurance programs in particular, typically provoked much criticism from the professionals involved with them. Moreover, the efforts of the Dutch medical association, the NMG, to influence state proposals met with little success. As a consequence, the NMG developed a health fund policy of its own, the demands of which newly established funds had to meet. The policy was designed to minimize lay control, improve fees and introduce an income limit to protect private practice. In the country’s cities, collective contracts were instrumental to the enforcement of the NMG’s conditions. However, the goal of creating a nationwide network of NMG funds was slow to materialize, maturing only: 1) because health fund regulation was expected after compulsory sick pay was introduced; and 2) due to the involvement of the trade union movement in the establishment of health funds. When the Decree on compulsory health insurance was promulgated in 1941, the NMG became the biggest health care insurer in the Netherlands, but this legislation ignored everything it had strived for, instead introducing a centralized, bureaucratic system, which left carrier organizations with virtually no capacity to plan their own policies.