Is a letter of recommendation from undergraduate professor different from the major I am applying to OK? I am a recent electrical and electronics engineering graduate. Although an engineering graduate, the major I am applying to is International Studies. Is it okay to get a recommendation letter from your engineering professor as that is my last place of study? I haven't worked anywhere so a recommendation letter from an employee is also out of question.
Sometimes when getting a letter of recommendation you have to do what you have to do.  Letters of recommendation are generally supposed to be speaking of you in the best light possible.  Ideally you would want one for the major your are applying to, and, even more ideally, from somebody who has supervised you in a research setting.  BUT, sometimes you would be better off getting a letter from somebody with a lower title if they can speak the world about you in a positive light.  Remember, that the purpose of recommendations is to describe competencies, skills, and other personality traits that will enable you to succeed in graduate school, something that grades can't show.  As such, you will want recommendations to be from the people who know you best, not just people in a specific department.  Personally, even though I had done a small amount of research at my undergraduate institution, I asked for two professors whom I had TA'd under to provide me with recommendations for an REU I participated in that subsequent summer.
You haven't provided too much about your situation, though, so it is kind of unclear what the exact situation is for you, such as why you are going from engineering to international studies or why you don't have any international studies faculty at your current institution to ask for recommendations or why you think the engineering faculty may be better for providing recommendations.