A total of 1,147 samples of blood serum, collected from porcine foetuses, were examined for the presence of immunoglobulin. The foetuses, from 182 sows, were sampled at abattoirs in Queensland during 1975. For detection and measurement of immunoglobulins, rabbit anti-pig serum and monospecific anti-pig IgG, anti-pig IgM and anti-pig IgA were employed in immunoelectrophoresis, double diffusion and single radial immuno-diffusion assays. Twenty-four foetuses (from 7 litters) had detectable IgG or IgM. None of the samples were positive for IgA. Two of the serums (from siblings) had high antibody titres to porcine parvovirus but in the remainder of the immunoglobulin-positive serums no antibody activity was detected.