A catalyst suitable for the gas-phase oxidation of organic compounds to α,β-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.