Mayor Job Cohen announced his decision to close the so-called coffee shops before the opening of a "weed summit" of representatives of the main Dutch cities who are debating the nation's long-standing tolerance policy.
Marijuana is technically illegal but can be sold in small amounts in designated cafes without fear of prosecution.
More than a quarter of the country's coffee shops are in Amsterdam, where they are a major tourist attraction.
Amsterdam spokeswoman Iris Reshef said the city did not have major problems with the coffee shops but had sent letters to the 43 shops within 250 metres of a high school, warning that they will have to close by the end of 2011 if they cannot successfully appeal the decision.
The cafes slated for closure include landmarks such as The Bulldog - a high-traffic shop operating on one of the city's main squares since 1985.
Report on Spiegel-online: Too close for comfort
According to an article in De Volkskrant
(De Volkskrant, 22.11.08, page 3:‘Ze weten heus wel dat we blowen, vijf minuten fietsen en je hebt het’), puples from the highschool next to the Bulldog have taken the distance to the Bulldog via Google maps: 300 meter and not 250, they said.
The headteacher is quoted: "We don't mind to have a coffee shop within a distance of 200m instead of dealers next to the school or even on the schoolyard."
More information at Radio Netherlands: Dutch mayors meet to discuss revamp of liberal drugs policy