The present invention relates generally to a method for assessing nucleic acid methylation, in particular DNA and RNA methylation. More particularly, the present invention relates to a method of either qualitatively or quantitatively assessing, with improved sensitivity, the cytosine methylation of partially methylated DNA or RNA. The method of the present invention is useful in a range of applications including, but not limited to, the diagnosis of conditions or monitoring of developmental phenotypes which are characterised by DNA or RNA methylation changes.