When nurses perform their tasks, they manage situations where maths knowledge is required. Such a situation is the calculation of medication dosage. Aim: The literature review of papers relevant with the mathematical knowledge and drug calculation skills of nurses and nursing students. Material-Method: A search of published research and review articles from January 1989 until March 2012, has been conducted in Pubmed database. The search terms used were: nurses, mathematics skills, numeracy skills and medication dosology calculation skills. Results: Literature review showed that many studies focus in the mathematical knowledge and drug dosage calculation competency of nursing students. Results from these studies revealed that nursing students had poor mathematical knowledge and drug dosage calculation skills. In contrast with students, professional nurses are more likely to have sufficient skills in drug calculations. Apart from the papers analyzing calculation skills' assessment, several studies examined educational interventions in the context of calculation skills enhancement. Accuracy and proficiency in the dosage calculation of medications is a preventive factor of errors made at medication preparation and administration. Conclusion: Mathematical knowledge and drug dosage calculation abilities are interrelated concepts and essential clinical skills for the nurse. The fact that nursing students do not have adequate skills for calculating medications' dosage, might be an issue that schools of nursing education should focus in. Further research of the drug dosage calculation skills is considered essential.