Optimum conditions have been established for isolation of ‘cryptic’ satellite DNA from the genome of pea ( Pisum sativum), using gradients of CS 2SO 4 containing silver ions. At an Ag + :DNA-P ratio ( R) of 0.1, and at alkaline pH, four fractions are obtained: mainband (buoyant density 1.437 g cm 3; 67% of total DNA), satellite I (buoyant density 1.582 g/cm 3; 7% of total DNA), satellite II (buoyant density 1.520 g/cm 3, 11% of total) and satellite III (buoyant density variable between 1.45 and 1.51 g/cm 3; 15% of total). The reiterated DNA content of these four fractions has been investigated by reassociation experiments conducted over a Cot range of 1 × 10 −5 to 2.0. All four fractions contain at least two kinetic components; each fraction, including the mainband, consists at least partly of highly reiterated DNA. Ribosomal RNA hybridizes only to the mainband.