The fluorescence fading and chromosome imaging method were used together to analyze chromosomal DNA contents (haploid set) in Pacific red abalone Haliotis rufescens (Archaeogastropoda: Haliotidae). The fluorescence intensity was measured each 1.6 sec in H. rufescens chromosomes (2 n = 36) stained with DAPI. The fluorescence of each chromosomal type was recorded using color digital images of 24 bits. These kind of images allowed converting the RGB (true color) images to pseudocolor images to quantify the fluorescence intensity by means of 256 levels of brightness. Algorithms built with MATLAB software were used to determine the area under the curve (fading function). Therefore, estimates of DNA contents in individual chromosome types were obtained. Their DNA contents were related with chromosomal sizes (P < 0.001). The DNA values found showed a range from 0.1106 ± 0.0045 pg (chromosome # 1) to 0.0890 ± 0.0060 pg (chromosome # 18). The genome size calculated for H. rufescens by sum of all chromosomal DNA contents was 1.77 ± 0.005 pg. This study describes an alternative imaging method to analyze the chromosome morphology and chromosomal DNA contents in molluscs, and represents an alternative approach to the lack of cell lines required in flow cytogenetics.