To store N bits of M.gtoreq.2 logical pages, the bits are interleaved and the interleaved bits are programmed to .left brkt-top.N/M.right brkt-bot. memory cells, M bits per cell. Preferably, the interleaving puts the same number of bits from each logical page into each bit-page of the .left brkt-top.N/M.right brkt-bot. cells. When the bits are read from the cells, the bits are de-interleaved. The interleaving may be deterministic or random, and may be effected by software or by dedicated hardware.