In response to the need for improved quality of vaccine inventory and client immunization records, barcodes containing a unique identifier and lot number will be placed on all vaccine vials in Canada. We conducted feasibility studies to examine integration of barcode scanning into inventory recording workflow for mass immunization clinics. During the 2010-2011 seasonal influenza vaccination campaign, Ontario public health units (PHUs) using an electronic immunization system were randomized to record clinic inventory data (including vaccine lot number and expiry date) through: (i) barcode scanning of vials; or (ii) drop-down menus. A third group of PHUs recording vaccine inventory on paper served as an observation arm. We visited a sample of clinics within each PHU to assess barcode readability, method efficiency and data quality. Clinic staff completed a survey examining method perceptions. We observed 20 clinics using barcode scanning to record inventory data (eight PHUs), 20 using drop-down menus (eight PHUs), and 21 using paper forms (five PHUs). Mean time spent recording data per vial was 4.3s using barcode scanners with 1.3 scan attempts per vial, 0.5s using drop-down menus, and 1.7s using paper. Few errors were observed. Sixty-four perception surveys were completed by inventory staff; barcode scanning users indicated fairly strong overall satisfaction with the method (74%), and the majority agreed that barcode scanning improved client safety (84%) and inventory record accuracy (77%). However, 38% of barcode scanning users felt that individually scanning vials took longer than the other approaches and 26% indicated that this increased time would discourage them from adopting the method. Our study demonstrated good readability of barcodes but scanning individual vials for high-volume clinics was time-consuming; modifying the process will improve feasibility to facilitate adoption in Canada, while serving as an example for other countries considering this technology.