An electronic sourcing system includes a computer that maintains a catalog database of data including product information (such as product identification and descriptive information) relating to catalog items available from vendor product catalogs, and a means for building (generating) a requisition including at least one requisitioned item. Information at least partially identifying an item desired to be requisitioned is entered by a user, and utilized by a means for searching the database for catalog items matching that information and for selecting at least one catalog item located as a result of the search. Text describing the catalog items, and images of the items, may be viewed. Data identifying selected catalog items are communicated to the requisition building means, which generates a requisition including entries for items corresponding to the selected catalog items. The system checks the availability in one or more inventory locations of the corresponding desired catalog items, and generates one or more purchase orders for desired items from inventory locations stocking the items.