The US H1B visa is a non-immigrant visa, which allows a US company to employ a foreign individual for up to six years. As applying for a non-immigration visa is generally quicker than applying for a US Green Card, staff required on long-term assignment in the US are often initially brought in using a non-immigrant visa such as the H1B visa.

Individuals can not apply for an H1B visa to allow them to work in the US. The employer must petition for entry of the employee. H1B visas are subject to annual numerical limits.

US employers may begin applying for the H-1B visa six months before the actual start date of the visa. Since the beginning of the FY 2007 is October 1, 2006, employers can apply as soon as April 1, 2006 for the FY 2007 cap, but the beneficiary cannot start work until October 1st.

The H1B visa is designed to be used for staff in "specialty occupations", that is those occupations which require a high degree of specialized knowledge. Generally at least the equivalent of a job-relevant 4-year US Bachelor's degree is required (this requirement can usually be met by having a 3-year degree and 3 years' relevant post-graduate experience). However, professionals such as lawyers, doctors, accountants and others must be licensed to practice in the state of intended employment – e.g. a lawyer must generally have passed the relevant state bar exam.

Non-graduates may be employed on an H1B visa where they can claim to be 'graduate equivalent' by virtue of twelve or more years' experience in the occupation.

Positions that are not "specialty occupations", or for which the candidate lacks the qualifications/experience for an H1B visa, may be filled using an H-2B visa. The disadvantage of the H-2B visa is that it requires 'labor certification' - an expensive and time consuming process that involves extensive advertising of the position, and satisfying the authorities that there are no US workers available to do the job. Also, H-2B visas are initially granted only for one year, extendable in one year increments to a maximum of 3 years. As each extension requires a new Labor Certification, it unsurprising that, of the annual quota of 66,000 H-2B visas, only a few thousand are ever issued.

New H1B legislation requires certain employers, called 'H1B dependent employers' to advertise positions in the USA before petitioning to employ H1B workers for those positions. H1B dependent employers are defined as those having more than 15% of their employees in H1B status (for firms with over 50 employees – small firms are allowed a higher percentage of H1B employees before becoming 'dependent'). In addition all new H1B petitions and 1st extensions of H1B's now require a fee (in addition to the usual filing fees) of US$1,000 to be paid, which will be used to fund a training program for resident US workers.

The initial visa may be granted for up to three years. It may then be extended, in the first instance for up to two further years, and eventually for one further year, to a maximum of six years. Those wishing to remain in the US for more than six years may, while still in the US on an H1B visa, apply for permanent residence (the "green card"): if such employees do not gain permanent residence, when the six year period runs out, they must live outside the US for at least one year before an application is made for them to enter on an H or an L visa.

Once a company has brought an employee to the US on an H1B visa, should the company dismiss that employee before the expiry of the visa, the company is liable for any reasonable costs that the employee incurs in moving him/herself, his/her effects, back to his/her last foreign residence. This provision covers only dismissal, it is not relevant when an employee chooses to resign.