Evidence of bioerosion in Middle Eocene larger foraminifera Nummulites obtusus (Sowerby) from Lakhpat, NW Kutch, India is documented here. Examined ichnofossils are shallow cylindrical borings in N. obtusus Form-B tests. These borings fall within the morphological range of ichnogenus Oichnus Bromley. Naming, behavioural interpretation (ethology) and possible biological affinity of borings in N. obtusus are discussed. Ichnofossils indicate that the sedimentation regime was characterised by a low rate.