Recent investigations of physical properties of ACo2As2 (A = Ca, Sr, Ba) indicate that Co-based arsenides could be a potential parent compound like the parent AFe2As2. While CaCo2As2 shows an A-type antiferromagnetism both SrCo2As2 and BaCo2As2 remains paramagnetic down to 1.3 K and 0.45 K, respectively. Inelastic neutron scattering reveal stripe spin fluctuations in SrCo2As2 similar to those found in parent AFe2As2. Because of high sensitivity of muons to extremely small magnetic field it would be of interest to investigate the magnetic correlations in SrCo2As2 and BaCo2As2 using muon spin relaxation (µSR) technique. We therefore propose to carry out µSR study on these two compounds using the MUSR spectrometer. For a comparative study we also plan to perform µSR study on CaCo2As2.