If you live or work in the Netherlands you have to hold a Dutch Basic Health Insurance Policy (Basisverzekering) within 4 months after arrival, even if you are already insured in another country. However, there are some exceptions to this rule.

You are free to choose your Health Insurance Provider and may change provider every year. 

Basic Dutch health insurance 
The Basic Dutch Health Insurance Policy (Basis-zorgverzekering) offers a universal package for every citizen in The Netherlands. This is regardless of gender, age and healthstatus. Health Insurance providers have to accept every citizen by law. They will therefore not ask information about your healthstatus or medical history for the registration. The insurance covers more or less every normal treatment provided by the Dutch healthcare. It is good to know that dentistry is not covered by the Basis Health Insurance. The Dutch government decides every year, what is covered by the Basic Health Insurance and what the compulsory excess (eigen risico) is.
You can take out an additional policy (aanvullende zorgverzekering) at extra costs, for coverage of some extra paramedical, dental and post-birth care. About 80% of the people do but calculate for yourself whether this is attractive.

If you don’t take out insurance while you are required to do so, you risk a fine.

Dutch Healthcare Insurance is also explained here in a simple, but comprehensive animation.

For more information go to Healthcare for Internationals or reed the brochure.

For those people who are spending their holidays in The Netherlands and are in need of medical services: they have to pay after treatment. This amount can be reimbursed from their own health- or travel-insurance.