Alleloscope is a method for allele-specific copy number estimation that can be applied to single cell DNA and ATAC sequencing data (separately or in combination). Allele-specific estimation allows for the more accurate delineation of copy number states and the detection of subclonal copy-neutral loss-of-heterozygosity and mirrored CNA events. On scATAC-seq data, Alleloscope allows integrative multi-omic analysis of allele-specific copy number and chromatin accessibility for the same cell.