Evidence of damage and repair in a Quaternary fossil brackish-marine ostracod is described. The specimen is a right valve of Bicornucythere bisanensis from the Laizhou Bay, eastern China, showing distortion in the posterior region, interpreted as a possible bite mark resulting from attempted predation on the ostracod. Comparison with undamaged specimens from the same assemblage suggests that the damage occurred just after the ostracod had moulted and was still in a 'soft-shell' state, before the new bivalved carapace was calcified, and that subsequent calcification preserved the resulting distortion of the reticulate surface ornament. This implies that the ostracod survived the damage and was able to heal and repair its shell. As far as we are aware, this is the first such example to be documented in Ostracoda although similar occurrences have been recorded in other fossil arthropods.