Résumé : The reactions (1) K+ p → K*(1420)p and (2) K+p → K*(1420)N*(1236) are studied at 5 GeV/c incident K+ momentum. The simultaneous fitting of the Kπ and K*(892)π decayy modes of the K* (1420) in the same production reaction makes it possible to eliminate 1- as the spin of the K*(1420). The most likely K*(1420) spin-parity assignment is 2+ although 3- cannot be excluded. The various decay branching ratios of the K*(1420) are determined. The ratio of the K*(892)π to the Kπ decay modes is found to be 0.9 ± 0.2. The peripheral production of the K*(1420) seems to be due predominantly to vector-meson exchange in reaction (1) and to pion exchange in reaction (2). © 1969.