Limited information on drug use indicates that medicines are not optimally used. Inadequate knowledge of medication uses may lead to overuse of medicines or patient non-compliance with a medicine regimen, and result in serious outcomes. The aim of this study was to assess the patients’ knowledge on dispensed medications in pharmacy at Port Moresby General Hospital (PMGH). This was a descriptive cross-sectional study utilizing a self-administered questionnaire adapted from the WHO “Guide to Good Prescribing Practical Manual”. The questionnaire sought to elicit major classes of medicines prescribed, knowledge of patients on indications, how to use the medicines, precautions and possible adverse events. A total of 130 patients from PMGH participated in this study. Although majority of patients (94.6%) knew the instructions on the use of the dispensed medicines in terms of route of administration, dosage and frequency of usage; only 74.6% of them knew the duration of medicines use. Further, 19.2% of participants did not know the indications for which their medicines were prescribed. Knowledge on adverse effects was also significantly low i.e 34.7%. Lack of understanding of warnings and precautions was rated at 42.3%. These figures may contribute to poor patient compliance and cause possible harm to the patients. The results demonstrated lack of adequate information given to patients on their prescribed medicines. It is recommended that prescribers be re-trained on the importance of giving adequate information on medications given to patients, particularly to patients with low educational background.