More than nine out of ten USPS customers described its customer service as either excellent, very good or good in the period between July 1st and September 30th.
Published earlier this week, the figures are the highest rating the service has received in four years.
The postal service will also be continuing on this rise with a new Customer Experience Measurement (CEM) program in the new year, according to a recent statement.
This will replace the old customer satisfaction service that has been in place for 18 years.
John Potter, the postmaster general, said that the results represented the services commitment to "customer service and satisfaction".
He added: "We will continue to improve [the] service. In fact, we have implemented an even more demanding service measurement system that will allow us to see more easily where we need to focus improvement efforts."
The new CEM service is designed to be able to evaluate every aspect of customer interaction within the USPS, from the process of buying stamps to the speed and nature of the service provided.