ParaPLoP 2010, a PLoP-style workshop on parallel programming patterns, was held March 30-31 in coordination with ChiliPLoP 2010 at Spirit in the Desert Lutheran Retreat Center in Carefree, AZ. ChiliPLoP is organized and co-sponsored by the Hillside Group, a group dedicated to BLAH. The call was for papers that described one or more patterns, outlined a pattern language, analyzed previously published patterns, described case studies of using patterns to develop parallel software, or presented experience mining patterns from significant parallel code implementations. Being a "PLoP-style workshop" meant that ParaPLoP was organized as a set of writer's workshops. The purpose of ParaPLoP was to help authors improve their papers. In a writer's workshop, the author of a paper is quiet during the discussion of a paper and listens to the rest of the workshop analyze it. Therefore, the papers you see here are not the same versions we discussed at ParaPLoP, but versions that the authors created based on the feedback they received. The writer's workshop form is very good at letting authors see how well their readers understand the paper, which helps them to make their papers even better. So, by reading these papers you can receive some benefit from ParaPLoP even if you did not attend it. The organizers of ParaPLoP are all working on a pattern language for parallel programming that we call Our Pattern Language for lack of a better name. Many of the papers at ParaPLoP are directly related to OPL, though some are additions to OPL and others are reactions against it or critiques of it. However, ParaPLoP was not intended to focus on OPL and so some of the papers are completely independent of it. Nevertheless, honesty compels us to admit that there is probably a bias in favor of OPL in these papers, for which we ask your pardon.