Iwatsuki (岩槻市; -shi) was a city located within Saitama Prefecture, Japan until it merged into the city of Saitama on April 1, 2005.
As of 2003, the city had an estimated population of 109,580 and the density of 2,229.05 persons per km². The total area was 49.16 km².
The city was founded on July 1, 1954.