Chloroplast gene expression is regulated at various steps including the synthesis, stabilization/ maturation and translation of plastid mRNAs. Nucleus-encoded gene products have been shown to be involved in this regulation via the formation of complexes with their cognate chloroplast RNA targets. As regulatory key factors, they usually accumulate to only low amounts. Here, we describe a strategy for the enrichment of native high molecular weight chloroplast ribonucleoprotein particles from Chlamydomonas reinhardtii by using consecutive gel filtration steps.