The decays of B-hadrons have been reconstructed using the charged part
icles recorded in the DELPHI silicon microstrip detector. The sum of t
he charges of the secondaries determines the charge of the B-hadron pa
rent. Some 232 114 multihadronic Z0 decays recorded during the 1991 ru
n of LEP at centre-of-mass energies between 88.2 GeV and 94.2 GeV yiel
d 253 B-hadron candidates with well-measured charge. From these the me
an lifetimes of neutral and charged B-hadrons are found to be 1.44 +/-
0.21(stat.) +/- 0.14(syst.) ps and 1.56 +/- 0.19(stat.) +/- 0.13(syst
.) ps respectively. The ratio of their lifetimes is 1.09(-0.23)+0.28 (
Stat.) +/- 0.11 (syst.). Under some assumptions on the abundance and l
ifetime of the LAMBDA(b)0 and B(s)0 states, the B0 and B+ lifetimes ar
e inferred.