To evaluate and analyze the handwritten outpatient prescriptions and associated error of omissions from four different hospitals in Oman. The study designed was an observational, retrospective and analysis of prescriptions was carried out by table and chart method. A total of 900 prescriptions were collected between April 2009 to July 2010. The type of error of omissions considered in this analysis includes all three important parts of prescriptions, i.e. superscription, inscription, and subscription. The most common type of superscription error of omission was found to be age (72.44%) and gender (32.66%). More than 46% of prescriptions were incomplete on direction for use, more than 22% of prescriptions were not having the information on dose, and more than 23% of prescriptions omitted the dosage forms of prescribed drugs. The date of dispensing of medications was omitted in all the prescriptions and more than 44% of prescriptions were missing the signature of dispenser. It was also found that more than 4% of prescriptions omitted the prescriber's signature and more than 18% of prescriptions omitted the date of prescription. We conclude from this study that the handwritten prescriptions were associated with significant frequency of minor and major prescription error of omissions.