Purpose To analyze and characterize data regarding the prevalence and types of outpatient drug-related problems (DRPs) found by clinical pharmacists after implementation of the Virtual Medicine Record in Cloud System (VMRCS). Methods A cross-sectional study regarding outpatient pharmaceutical care was conducted at a medical center in Taiwan. Patients aged >20 years old with multiple chronic diseases and polypharmacy were enrolled. In Stage I (1 October-31 December 2014), patients received pharmaceutical care according to prescription data accessed online in the VMRCS. In Stage II (1 June-31 August 2015), the VMRCS were pre-download and arranged to the institute's required format, facilitated DRP detection. Clinical pharmacists then reviewed and evaluated the prescription data through pre-downloaded VMRCS. Overall, 1539 and 1600 prescriptions were evaluated in these two stages, respectively. DRPs were recorded using the Pharmaceutical Care Network Europe (PCNE)-DRP. Results DRPs were found for 50.2% of patients in Stage I and 55.2% in Stage II (p< 0.05) and were most frequently encountered for "Drugs for the cardiovascular system" and caused by " Inappropriate duplication of therapeutic group or active ingredient." In terms of problems, incidence of "Unnecessary drug treatment" was highest. Duplicate medications were most frequently seen for " Drugs for acid-related disorders."The efficiency to identify DRPs was at least 2.4 times higher with pre-downloaded prescription data than with real-time online queries. Conclusions With VMRCS, DRPs were more easily identified whether patients received medical care in the same hospital or not. DRPs could be efficiently prevented through the use of pre-downloaded patient prescription data. Copyright c 2016 John Wiley & Sons, Ltd.