Trace fossils are those details preserved in rocks that are indirect evidence of life. While we are most familiar with relatively spectacular fossil remains such as bones and entire skeletons, trace fossils are often less dramatic. Trace fossils include burrows, track marks, coprolites (fossilized feces), stromatolites (fossilized algal mounds), and rhizoliths or rhizocretions (fossil remains of roots).

The study of trace remains is called ichnology, which is divided into paleoichology, or the study of fossil traces, and neoichology, the study of modern trace remains.

The science of ichology is very difficult, as many trace remains cannot be positively assigned to a specific organism. Further, trace remains such as burrows can make the work for paleontologists and geologists more difficult as they rework sediments, causing older strata to be mixed with a younger strata. This can cause some confusion in interpretation unless viewed in context.

Pseudofossils are sometimes confused as being trace fossils.