A prospective descriptive observational study using WHO indicator forms and questionnaire was carried out in Kibaha district public primary health care facilities. We assessed knowledge about drugs in mothers/guardians of sick children under age five years immediately after consulting clinicians and after receiving drugs from the dispenser. The questionnaires had closed- and open-ended questions. Interviews were administered by trained nurses and the authors. The prescribing, dispensing practices, including drug labeling and instructions given to mothers/guardians on how to use drugs at home, in these health facilities which are under the Essential Drugs Program (EDP), was assessed. A total of 652 prescriptions from mothers/guardians with sick children under age five years were observed, recorded and analyzed. Prescribing indicators were used as stipulated by the WHO/DAP/93.1 how to investigate drug use in health facilities. The diagnosis for malaria cases made by the clinicians on average per facility were as follows: malaria alone 25, diarrhea alone 3, pneumonia alone 3, malaria and diarrhea 4 cases, malaria and pneumonia 2 cases and malaria and other conditions 14 cases. The average number of drugs per prescription in these facilities was 2.3 and the percentage generic prescribing was 87.0, antibiotics 30.5, and injections 26.2, with 93.5 % of all prescribed drugs being within the Essential Drugs List (EDL). The overall average dispensing time was 1.4 minutes per patient, of the drugs prescribed, 54.7 % were dispensed, whereas 21.4 % of drugs dispensed to mothers/guardians were adequately labeled, and 37.2 % of mothers knew how to administer drugs correctly to their sick children after receiving the drugs from the dispenser. These results suggest the need for educational intervention for prescribers (health care providers) on rational prescribing of drugs, such as antimalarials, antibiotics, injections, proper dispensing, and adequate labeling drugs in packets, while the dispensing time for drugs was too short. It is necessary to correct these malpractices of irrational prescribing and dispensing drugs for treatment of malaria and other childhood illnesses in public primary health care facilities (PHC). Furthermore, inadequate physical examination and short consultation time needs to be improved. There is a need to advise the Ministry of Health to develop health education programs on a regular basis for all health care providers in the country and mothers/guardians of children in general public/rural communities on how to use/administer antimalarials and other drugs at home. All these can be achieved through well planned health education training programs.