Light-scattering measurements in three different frontal zones are presented, namely, in the coastal upwelling areas outside northwest Africa and central Peru and in the open ocean Antarctic Polar Front in Drake Passage. The observations were made with in situ instrumentation, reaching depths of 1000 m, in conjunction with CTD profiles, in repeated sections across the frontal zone. The scattering distributions, giving the distribution of suspended matter, are compared with the temperature distributions. In the African upwelling region there was good correspondence between these two distributions. Frontal zones were present over the shelf break and slope. The Peru upwelling area was quite different with only very limited correspondence between the temperature and scattering distributions and weak indications of frontal zones over the slope. Across the polar front a markedly layered structure was observed with a clear correspondence between temperature and scattering. The cold water south of the front contained more scattering material than the warm water north of the front. The layers could be traced across the front. In addition, several distinct patches of high and low scattering were observed in the vicinity of the front, indicating mixing across the front. The results show that scattering observations can reflect processes occurring in frontal zones and that it is useful to include such observations in programs aimed at elucidating various physical, chemical, and biological processes in frontal zones.