The product of gene 33 is essential for the regulation of late transcription and gene product 59 is required in recombination, DNA repair and replication. The exact functions of both proteins are not known. Restriction fragments spanning the genomic area of genes 33 and 59 have been cloned into phage M13 and a 4.9 kb nucleotide sequence has been determined. Translation of the DNA sequence predicted that gp33 contains 112 amino acids with a mol.wt. of 12.816 kd while gp59 is composed of 217 amino acids adding up to a mol.wt. of 25.967 kd. The genomic area studied here also contains 3 open reading frames of genes not identified to date and it is thought to include the NH2-terminal part of g34. One of the open reading frames seems to code for the 10 kd protein, probably involved in the regulation of transcription of bacteriophage T4. This protein is predicted to consist of 89 amino acid residues with a mol.wt. of 10.376 kd. Gene 33 and the gene for the 10 kd protein were cloned separately on high expression vectors resulting in over-production of the two proteins.