Abstract: In an associative memory, each cell 20 (FIG. 2) includes a recirculatory shift register 30 in which information is stored, a comparator 31 for comparing the stored information with a key fed on line 22, a gate 32 for passing the results of the comparison only in a key field defined by key field signals on line 23, and a flip-flop 33 which is set to 1 if the comparison fails. Flip-flop 33 controls reading from the cell. A flip-flop 37 is used to record whether the cell is full or empty, and a compare chain 40a, 40b passing through all cells in sequence is energized onwards from the first cell in which comparison is successful.A further development permits sequential retrieval and searching for the next key above a desired key if the desired key itself is not in the memory.