OBJECTIVES: Automation of pharmacy processes can help to reduce medication errors as well as improve the efficacy of the medication picking, packing and labeling process. Since June 2012, two drug dispensing systems (DDS) began operations in the Singapore General Hospital Specialist Outpatient Clinic Pharmacy. This study sought to evaluate the impact of the DDS on safety and efficacy in the pharmacy. METHODS: The primary outcome of this study was the safety of the prescription filling process measured in terms of percentage prevented dispensing incidents contributed by DDS or manual picking of medications. The secondary outcome was the efficacy of the medication picking, packing and labeling process measured in terms of picking efficiency of each full time equivalent (FTE) when assigned to either the DDS or manual picking stations. Data pertaining to the primary and secondary outcomes between January and December 2013 were collected and analyzed. RESULTS: The median percentage prevented dispensing incidents per month committed by manual picking (0.27) was significantly higher (p < 0.05) than the DDS (0.00). DDS had greater picking efficiency with each FTE in the DDS having an average of 6175 picks per month which was significantly higher (p < 0.05) than each FTE in the manual picking stations which had an average of 4867 picks per month. CONCLUSIONS: In summary, installation of DDS in an outpatient pharmacy improved safety of the prescription filling process by automating the medication picking, packing and labeling process thus minimizing human errors. The efficacy of the medication picking, packing and labeling process was also improved by the DDS as there were continuous efforts to boost their productivity as well as being more reliable and able to handle fluctuations in patient load better.