Abstract: A portable meter-billing machine, for issuing bills to the customers of public utilities such as town gas and electricity which are supplied to the consumers through meters at the consumer's premises, comprises a portable carrying case for the official meter reader to carry to successive premises, the case being provided with a keyboard for entering the new meter reading at the premises of each successive consumer and housing a data memory storing the previous meter-readings of the respective consumers, a program memory storing a billing program and tariff data, a microprocessor and a bill printer controlled by the microprocessor in accordance with the billing program. The machine is responsive to a new meter reading for a consumer being entered on the keyboard to prepare billing data from the previous meter reading stored for that consumer and the stored billing program and tariff data and to print a corresponding bill for that consumer.