PhD in the US with an MSc from another country: coursework exemption? I'm currently studying for an MSc in theoretical particle physics in Israel. After I finish it I would like to study for a PhD abroad.

In the UK it seems that a PhD degree does not generally require taking any courses. In the US, on the other hand, all of the PhD programs I checked require at least one or two years of coursework as part of the PhD studies, and the actual research only starts after that.

My question is: do you know whether universities in the US allow students with an MSc degree, who have already done most or all of the graduate courses as part of that degree (and got good grades), to begin research immediately instead of taking the courses again? I really don't want to repeat the courses and waste two years.
It depends on the department. I have been looking at various applied mathematics departments in the USA and all of them want PhD students to go through the coursework and obtain an MS, even if they already did a masters degree before.

I think in general, there is no chance to skip coursework. This is probably because different universities have different standards and syllabuses for the same course. And they want to ensure everyone is up to the same standard and have taken the same syllabus.

But do check with the department, there are always exceptions.

P.S.

However, it doesn't have to be a "waste" of two years. The level of the course might be higher and you are probably able to choose different courses to get broader experiences. If all else fails and you are able to ace all the courses with no problem, you can always spend the extra time looking for a thesis adviser or find research collaborators.