Mass spectrometry has been used in the study of synthetic polymer systems since the 1960s. The application has been, for the most part, limited to the characterisation of polymer additive systems and polymers that had either been chemically or thermally degraded. The advent of newer ionisation approaches, coupled with the development of analyser technology, has led to the reappraisal of mass spectrometry for this work. Molecular weight distributions have been obtained and information on end groups and chemical variation with molecular weight has been measured. Polymer microstructure has been probed with information obtained on partial and, in some cases, complete sequence for oligomeric systems. Fundamental work to support these developments is needed and is being carded out. Information on gas-phase polymer conformations has been obtained and an important link with calculation established. The future of the approach, particularly when used in conjunction with other complimentary chromatographic and spectroscopic techniques, looks promising.