I examine the long‐term impact of a real estate bubble on the land‐use patterns of Tokyo and Osaka from 1980 to 2003 and find that fluctuations in land prices reflected changing demand for commercial land relative to that for residential land, which, in turn, affected housing supply and residential location choices. During the real estate bubble, land developers favored commercial over residential development because the perceived productive value of commercial land increased sharply. Thus, daytime population in central cities increased and residential population fell. During the economic downturn, however, the demand for commercial space fell, houses were favored by land developers and residents were recentralized. My causal estimates show that the commercial‐to‐residential land‐use conversion can explain approximately 9% to 16% of the housing starts after the bubble burst in Tokyo and Osaka, and their populations would have been reduced by 2% to 3% otherwise. The effect is more prominent in their central business districts. My findings provide a novel explanation for the recent changes in central neighbourhoods.