A patent attorney is an attorney who has specialized skills and qualifications necessary for representing clients in obtaining and enforcing patents and acting in all matters and procedures relating to patent law and practice. The term is used differently in different countries, and the skills, qualifications and job profiles differ from country to country.

Practice includes filing of patent applications on behalf of inventors, prosecuting patent applications on behalf of inventors, and participating in administrative appeals and other proceedings before the United States Patent & Trade Office (USPTO) examiners and Board of Patent Appeals and Interferences boards (BPAI). The patent office in each country sets its own standards for who may practice and requires that any person who practices become registered.

In the US to be registered as a patent attorney, one must pass the USPTO registration examination. This exam is commonly referred to as the "patent bar". The exam tests a candidate's knowledge of patent law and USPTO rules and procedures. A candidate must also have adequate scientific and technical training (bachelor's degree in the natural sciences e.g. physics or engineering) to understand a client's invention. Patent attorneys are also admitted to the practice of law in at least one state or territory of the United States.

In UK Qualification is achieved by passing (or gaining an exemption from by passing certain university courses) the foundation level papers, and the advanced level papers. Almost the same applies in countries like Canada, Australia, New Zealand Japan, Singapore and other European countries. Some countries require the attorneys to train under experienced attorneys before becoming a full fledged registered patent attorney. In UK a patent attorney and patent agent have the same connotations while in the US they have different meanings. Although a European Patent Office (EPO) does exist, each European country has different qualification requirements at their national level.
EPO maintains a database of Registered Attorneys so does the Chartered Institute of Attorney in the UK. In the US a database of patent attorneys can be found at the USPTO website.

Interestingly, all countries require the attorneys to possess “good moral character”. This is, in part, because of the confidential nature of the inventions submitted by inventors.

Most law firms that recruit patent attorneys require them to have three additional characters. Be enthusiastic, have a good academic record and have great communication skills.

Patent attorneys can additionally provide legal services outside the Patent Office. These services include advising clients on legal matters related to the invention such as to file law suits on behalf of clients against infringers and defend clients against claims of infringement. These services also include appealing BPAI’s decisions to a court and drafting legal opinions as to whether a competitor is infringing the client’s patent (infringement opinion), whether the client’s product is infringing a competitor’s patent (non-infringement opinion), whether the client’s product is infringing any patent (clear-to-operate opinion), whether a patent is valid (validity opinion) and whether an invention is patentable (patentability opinion). Patent agents cannot provide legal services of this nature, nor can they represent clients before the Trademark Office section of the USPTO.

Most patent attorneys are hired by inventors for a three fold purpose, namely, searching national and international patents and printed publications, preparing patent applications (the most important step), prosecuting patent applications including appeals to the BPAI, and post issuance matters.