MicroRNAs are key regulators of gene expression in diverse biological processes and their importance in embryonic stem cells is indisputable. New 'next-generation' technologies such as Illumina massively parallel sequencing offer vast improvements, in both scale and sensitivity, to microRNA profiling studies. We describe a detailed procedure for the preparation of small RNA libraries for Illumina sequencing. We further comment on approaches for analyzing the resultant sequence data for measuring microRNA abundance.