Abstract: The present invention provides a process for the catalytic cracking of an olefin-rich feedstock which is selective towards light olefins in the effluent, the process comprising contacting a hydrocarbon feedstock containing one or more olefins, with a catalyst made of a phosphorus-modified zeolite (A), to produce an effluent with an olefin content of lower molecular weight than that of the feedstock, wherein said phosphorous modified zeolite (A) is made by a process comprising in that order: selecting a zeolite with low Si/Al ratio (advantageously lower than 30) among H+ or NH4+-form of MFI, MEL, FER, MOR, clinoptilolite, said zeolite having been made preferably without direct addition of organic template; steaming at a temperature ranging from 400 to 870° C. for 0.01-200 h; leaching with an aqueous acid solution containing the source of P at conditions effective to remove a substantial part of Al from the zeolite and to introduce at least 0.