A series of observations of the X-ray source 3U 0352 + 30 made with the Copernicus and Ariel 5 satellites are reported. We find evidence for 13·9-min and 22-hr modulations of the X-ray flux. The data also indicate long- and short-term changes in the slope of the X-ray spectrum and the amount of low-energy absorption. The implications of these results are discussed, especially for the proposed identification of the X-ray source with X Per.