Experimental data on the linear thermal expansion between 20 and 50�C of specimens of high-purity chromium confirm the existence of an anomaly centred at 38 �C. The exact shape of this expansion anomaly between about 37 and 39�C varies markedly from sample to sample, but outside this narrow temperature interval the behaviour is more regular and seemingly related to antiferromagnetic ordering. Data on expansion are compared with other recent observations on heat capacity, magnetic susceptibility, and electrical resistivity of high-purity chromium. It is suggested that an electronic term in the expansion coefficient, observed below 20 oK to be negative, is sensitive to band structure and may be partly responsible for the change in expansion coefficient.