The intelligence gathering tends to be focused on the the illegal acquisition of information on Swedish politics, defense, economy, technology, science, or about refugees, according to security service Säpo's annual report for 2010, released on Thursday.
Agents from foreign states also attempted to influence Swedish policymakers, or tried to purchase Swedish businesses in order to gain information or technology.
At the same time, Säpo also ramped up efforts to prevent foreign agents from spying on refugees.
Last year Säpo investigated 800 people seeking asylum in Sweden for possible connections to efforts to spy on refugees already in the country, a figure up by 120 from the previous year.
The probes stopped several cases of refugee espionage, according to regional newspaper Sydsvenskan.
Säpo suspected that the people stopped wanted to enter Sweden to spy on countrymen who had previously been granted asylum.
In a number of cases, Säpo made sure the Migration Board (Migrationsverket) refrained from issuing visas to individuals the security service suspected of being foreign intelligence agents.