Rankings different on google.com in US and in India

A serious issue I noticed with keyword rankings recently put me in a question. When I searched rankings on www.google.com from India, it was showing in the first page of Google. I performed the same action in a US computer and the results were entirely different. I think this is going to be serous issue when we work for clients outside our country. If anybody else is experiencig the same problem, please post here so that we can trace out a solution for this.