Background Information I would soon be graduating with an engineering degree from a "no name" university somewhere in Nigeria. My performance during my degree was above average. I am hoping to apply for a PhD program in US. The professors with whom I interact with regularly (with PhD's from schools in the US), have been giving me a resounding warning about applying to schools that clearly do not want and will never admit me because of the school's unpopularity and country of origin. One particular professor told me that Bachelor's degrees from this part of the world are not at all trusted and treated with disdain. I know lot's of schools encourage everybody to apply, but the exchange rates are not friendly, and I don't want to burn the scarce resources I have QUESTIONS 1. Does country of undergraduate study matter to the graduate admissions committee? 2. Do schools in the US give off hints that applicants from certain backgrounds need not apply? 3. With the difference in educational standards, do I stand a chance at all, even if i find a school willing to admit me?
At least in my department/school in the U.S., we have several individuals from African countries studying for doctoral degrees. I'm a little concerned that there seems to be a disconnect between what you say about your performance (above average) and what your professors are saying (no one would want someone like you, possibly because of where you studied).
As far as I can tell, most schools in the U.S. encourage individuals from diverse backgrounds to apply for their programs, including graduate school. So, I would not make a blanket statement that your country of origin and/or background is an immediate disqualification.
Regarding your academic background, even U.S. colleges differ in terms of academic programs and rigor. That is why the graduate school admissions process involves many different parts, including standardized test scores, interviews, and/or letters of recommendation, that help the admissions committee get a more complete picture of you and how you may fit within the program.
I'm going to give you a more practical and direct answer than Florian.
There is not enough information in your post to know whether or not it would be worth your time applying to US graduate schools. There are a number of options to consider, but you should get in contact first with people in your field of interest, because everyone here only knows about their own field.
I wouldn't buy into the "we encourage diverse applicants" mantra though - uncertainty from an unknown program where the professors aren't excited about you is not a good sign. Ask about possible master degree programs... many non-Americans get 1 or 2 masters degrees in my field before applying to top US graduate schools (2 if they are from very poor backgrounds like you, as they cant get into an elite masters the first time around). In my field schools that admit from out of the country typically admit from 2 or 3 masters programs (aside from the very best one) that they particularly like. Furthermore, in my field I've never heard of a student with only a bachelors from a third world country being admitted to a higher ranked program (not sure about the lower ranked ones).
So yes - country of undergraduate study matters because the school you went to is very important. The way that non-Americans make up for this fact is by doing masters degrees, at least in my field.
A last piece of advice: go to the graduate programs of the schools you like in the US. Look at their graduate student's CVs. The job market candidates should have all their stuff posted soon if not already. Look at their education background. This is the best signal a university can send you about their standards.