Can I patent a phrase on a t-shirt?

See my response to your identical question.

No. Patents do not protect phrases and written expressions. Phrases used in connection with a tee shirt may be eligible for either trademark or copyright protection provided the requirements for registration of each are met. But patent protection is not available for this. If you invented a unique process for actually making the tee shirt or applying the phrase, then you would be in the patent realm.

No. Patents apply to inventions. You also cannot copyright a phrase. Copyrights apply to works of original creativity fixed in a tangible medium of expression. Short phrases do not have the requisite creativity, and you admit you are not the creator, anyway. You also cannot normally trademark a T-shirt phrase. Descriptive and generic phrases are not usually indicators of source but rather of concepts, thoughts, expressions, or opinions which are part of public speech and not exclusive to anyone like you. Only through long continuous exclusive use can a phrase gain the requisite "secondary meaning" as being associated primarily with one single source. [e.g. JUST DO IT is associated with NIKE]. You need to be sure any phrase you use is not one that is associated with a company or person that would enforce their rights against you. An IP lawyer will be able to research that and give you reliable advice.

Phrases are not patentable inventions. See USPTO's description of what can be patented here: http://www.uspto.gov/inventors/patents.jsp

It all depends if someone else is claiming a legal right to the phrase. See http://www.hollywoodreporter.com/news/lionsgate-asserts-trademark-claim-dirty-148546 which refers to Lionsgate suing several companies for selling merchandise featuring the phrase "Nobody puts Baby in a corner" from the film 'Dirty Dancing'. Lionsgate asserted a trademark claim in this case. Copyrights on phrases is an interesting question of law as I still believe this issue is unclear as it depends on the phrase itself and how the phrase is used: see http://fairuse.stanford.edu/2003/09/09/copyright_protection_for_short/ for more details. As explained above there is no patent protection for a phrase, patents only apply to useful things, aesthetic designs and plants (asexually reproduced ones in particular). There is also remaining question: Can you yourself file for the phrase as a trademark? Again that would be based on the phrase and the use of the phrase. A good non-US example of that in the UK is the "Keep Calm and Carry On" phrase over which numerous companies are trying to claim in one for or another... Good Luck

Phrases are not patentable. A catch phrase is essentially a trademark. Trademarks are protected as a form of property. Owners of valid trademarks are granted exclusive rights to their use in commerce. As with copyrights, legal rights arise without the actual filing. But unlike copyrights, trademark rights don't begin at the moment a word, symbol, or phrase is first written on a tangible form. Trademark rights derive from the actual use of a distinctive mark in commerce.