With respect to this Special Scheme, a self-employed or autonomous worker is one who habitually, personally and directly performs a profit-driven economic activity, without an employment contract and may use the paid service of other people, whether or not the owner of an individual or family company.

It is assumed, unless otherwise proven, that the interested party is a self-employed worker when he or she owns an establishment open to the public as the owner, tenant, usufructuary or similar.

Law 18/2007 of 4 July establishes, within the Special Scheme for Self-Employed or Autonomous Workers, and with effect from 1 January 2008, the Special System for Self-Employed Agricultural Workers, which will include self-employed agricultural workers over the age of 18. Art. 324 of the consolidated text of the General Social Security Act establishes the following requirements for inclusion:

• They must own an agricultural holding and derive at least 50 percent of their total income from agricultural or other complementary activities, and this part of their income must derive directly from the agricultural activity carried out on their holding and must not be less than 25 percent of their total income.
• The working time spent on agricultural activities must be more than half of their total working time.
• That the net annual returns obtained from the agricultural holding by each holder of the holding does not exceed an amount equivalent to 75% of the amount, on an annual basis, of the maximum contribution basis for the General Social Security Scheme in force in the financial year in which it is checked
  
• Carry out agricultural work even if they a worker employed by another person, provided that there are no more than two workers paying contributions on a monthly basis or, in the case of workers paying contributions in accordance with article 255, that the total number of actual days worked does not exceed 546 in a year, calculated from 1 January to 31 December of each year.

• Workers over 18 years of age who perform a for-profit economic activity in a regular, personal, and direct manner, without being subject to an employment contract. 
• The spouse and relatives up to the second degree, inclusive (for workers in the Special Scheme for Self-Employed Workers), up to the third degree by consanguinity, affinity, and adoption who work with the self-employed worker in a regular, personal, and direct manner and are not wage earners. 
• Authors of books. 
• Self-employed workers who are economically dependent and are referred to in Chapter III of Title II of Law 20/2007 of 11 July.
• Foreign self-employed workers who reside and legally conduct their activity in Spanish territory.  
• Professionals who conduct, on their own behalf, an activity which requires membership of a Professional Association whose collective has become integrated within the Special Scheme for Self-employed Workers. 
• Professionals who conduct, on their own behalf, an activity which requires membership of a Professional Association whose collective has not become integrated within the Social Security Special Regime for Self-employed Workers, with the following special characteristics:

If the start of the activity by a professional with an association took place between 10th November 1995 and 31st December 1998, if affiliation to the above-mentioned Special Regime was not compulsory prior to this last date, it should have been requested during the first quarter of 1999, becoming effective from the first day of the month in which the application was made. If the application was made within the above-mentioned period, the effects of the late affiliations are those specified by law, with the starting date of the activity set as 1st January 1999.

Despite the specifications in the preceding paragraphs, professionals with associations who choose or have chosen to become affiliated to the Social Welfare Mutual Society set up by the corresponding Professional Association are exempt from the obligation to become affiliated to the Special Regime for Self-employed Workers, provided that this Mutual Society is one of those organised prior to 10th November 1995. If the interested party chooses not to become affiliated to this Mutual Society, while entitled to do so, he or she may not exercise such option later.

• Associates of regular joint companies and collective associates of limited partnership companies.
• Associate workers of Associated Work Co-operatives, when the latter choose this Regime in their bylaws. In this case, the minimum age for inclusion within the Special Regime is 16. 
• Communal partners or partners of communities of property and irregular civil companies. 
• Those who perform management or administration functions arising from the position of member of the Board of Directors or administrator, or who perform other services for a capitalist trading company, for profit and in a regular, personal, and direct manner, provided that they have effective, direct or indirect, control of the company. This is understood to mean, in all cases when this circumstance occurs, that the worker's shares or stock represent at least one half of the share capital.

It is presumed, unless otherwise proven, that the worker has effective control of the company when any of the following circumstances are met:

- At least one half of the capital of the company for which he or she performs services is distributed among partners with whom he or she lives, and to whom she or she is related by marriage or kinship by consanguinity, affinity, or adoption, up to the second degree.

- His or her share of the share capital is equal to or greater than one third.

- His or her share of the share capital is equal to or greater than one quarter, if he or she has company management and administration functions assigned.

In those cases where the preceding circumstances are not met, the Administration may prove, with any type of evidence, that the worker has effective control of the company.

• Associate workers of worker-owned companies, when their share in the share capital, together with that of their spouse and relatives by consanguinity, affinity, or adoption up to the second degree, with whom they live, is at least fifty percent, unless they can prove that effective control of the company requires the participation of persons other than family relations.

Self-employed workers whose activity as such leads to their being included in other Social Security schemes are excluded from this Special Scheme.