Can you be denied an organ transplant if you are a smoker?

Not exactly: Eligibility for transplant differs in countries, but in the us smoking could be one reason to be denied, but decisions are based on lots of different factors. Surgery makes healing more difficult, increases chances of bad reactions to drugs, and itself causes organ damage. Heart and/or lung transplants usually require an effort to stop smoking, which every smoker should seriously consider anyway.

Yes: Smoking will cause complications in the vascular supply to organs. Organs are a limited resouce and not everyone that needs one gets one. Surgeons have to make the hard decision of who to transplant. Many centers don't transplant smokers because outcomes are worse than for non-smokers. Smoking is a choice you make about your own health. If you choose to smoke you must live with the consquences.