Corn yields have increased due to both genetic and management factors. Several "era" or "decade" studies have been conducted to determine the rate of yield gain by growing hybrids representing a wide range in release dates at the same sites under a wide array of environmental conditions. Adoption of no-till and strip-till systems is growing, but no era studies have been conducted comparing no-till/strip till and conventional systems. For a preliminary comparison of yield gains for these systems, linear regressions were determined for National Corn Growers Association (NCGA) contest-winning yields in no-till/strip till and conventional tillage divisions for several Midwest states using results from 1983 to 2006. Contest-winning yields increased with both systems in most states, but the rate of gain was frequently greater with no till. This difference may be due to genetic enhancements such as stress emergence tolerance and disease resistance, but is also likely due to development of improved no-till management practices by corn growers.