A method for storage and transport of LPG on LPG carriers, in particular two cargoes of different LPG types on same shipment, having reliquefaction units in which vaporized gases are condensed and then returned into at least one cargo tank for the respective LPG cargo type. The method is further comprising: using the reliquefaction units, at a minimum one running, as to condense vapor from the first cargo type; passing the condensed vapor through a heat exchanger; simultaneously flowing vapor from the second cargo type through the heat exchanger as to condense vapor by means of heat exchanging with the condensed vapor; and returning the condensed vapors leaving the heat exchanger back into the respective cargo types. The present invention is also disclosing a system for storage and transport of LPG on LPG carriers.