New physics intt¯spin correlations at the Fermilab Tevatron

We show that the angular distributions of leptons or jets due to $t\overline{t}$ spin correlations allow a determination of the top quark chromomagnetic moment κ with an accuracy of order 0.1. The method is quite insensitive to background, event reconstruction, and other experimental uncertainties. The total event number is important, so we suggest the inclusion of all-hadronic events.