a least cost routing system comprises at least one telephone dialing unit , at least one least cost router and a database updating unit . the telephone dialing unit dials a telephone number to place a telephone call . each least cost router has a corresponding routing database of tariffs of telephone service providers and determines , from information in its corresponding routing database , which telephone service provider or providers to utilize to execute the telephone call . the database updating unit electronically updates tariff information into each of the routing databases shortly after updated tariff information is entered therein .