Double-stranded cDNA to embryonic chick procollagen mRNAs was synthesized by using the avian myeloblastosis viral reverse transcriptase. After ligation to chemically synthesized decanucleotides containing the HindIII restriction site, these double-stranded cDNA sequences were inserted into the HindIII site of pBR322. The recombinant plasmids were then used to transform Escherichia coli xl776 and recombinants containing procollagen cDNA sequences identified by colony hybridization to 32P-labeled procollagen cDNA. In addition to the three pro α2 collagen cDNA clones described recently (Lehrach et al., 1978) three additional recombinant plasmids pCg26, pCgl, and pCg54 with inserts 640, 850, and 1100 base pairs long have been identified. Their sequence homology has been determined by restriction mapping and by DNA sequencing. pCg54 has been positively identified as a pro al collagen cDNA clone by partial DNA sequencing of its ends: it has a sequence coding for residues 811-858 in the chick al chain near one end. pCg54 overlaps pCgl by 250 nucleotides and together these extend about 1500 nucleotides from the poly(A) end of pro α1 collagen messenger RNA. © 1979, American Chemical Society. All rights reserved.