A study of the beta decay of 143Cs and ~'~3Ba fission products was undertaken by the use of two on-line mass-separators OSTIS and OSIRIS. Level schemes for 143Ba and 143La are deduced from gamma and conversion electron spectra, 7-7 and/%7 coincidences. Q~ values and ground state beta feedings were also measured. The nuclei l'~3La and 143Ba are tentatively inserted in a systematic of odd-even nuclei around A = 143 and even-odd nuclei with 87 neutrons respectively.