Integrin alpha1beta1 is one of the main collagen receptors in many cell types. A fast large-scale production, purification and crystallization method for the integrin alpha1 I domain is reported here. The alpha1 I domain was crystallized using the vapour-diffusion method with a reservoir solution containing a mixture of PEG 4000, sodium acetate, glycerol and Tris-HCl buffer. The crystals belong to the C2 space group, with unit-cell parameters a = 74.5, b = 81.9, c = 37.3 A, alpha = gamma = 90.0, beta = 90.8 degrees. The crystals diffract to 2.0 A and a 94.2% complete data set to 2.2 A has been collected from a single crystal with an Rmerge of 5.8%.