The price of a typical home dropped 0.1 per cent from March to £165,586, the research said.
However, the figure is 0.9 per cent higher than April 2012.
“House prices were little changed in April, declining by 0.1 per cent compared to March after taking account of usual seasonal effects,” said Robert Gardner, Nationwide's chief economist.
“Nevertheless, there is some evidence that activity and prices have gained some momentum in recent months.
“The three month on three month measure of house prices, which is a smoother measure of the underlying trend, has been in positive territory since October last year. The annual rate of house price growth also remained in positive territory, with prices 0.9 per cent higher than April 2012.
“Similarly, the number of mortgage approvals has edged up from the levels prevailing last year and there are reasons for optimism that activity levels will continue to strengthen in the months ahead.”