The four-hour theme evening on December 2nd consisted of three documentaries, including Oliver Stone's Comandante, and a ten-minute studio debate between a former senior member of the Left Party and a Cuban writer.
In a ruling released on Monday, the Swedish Broadcasting Commission said that the evening broke the requirement for television productions to be politically balanced.
"While certain critical views of Fidel Castro and his regime were put forward in the studio discussion, the question of human rights for example was never tackled, either in this section or elsewhere in the broadcast," the commission wrote in its decision.
"A programme schedule in which a controversial political leader is allowed to put forward his message in two long programmes in the same evening requires...some kind of balancing element," the ruling continued.
SVT, Sweden's public-service television channel, received 19 complaints following the broadcast. Those who complained said that the programmes gave a "one-sided and uncritical" view of Fidel Castro and the situation on Cuba.
Two viewers also took exception to promotional text on SVT's website which claimed that 2nd December would see "double celebrations for Cuba: firstly the celebrations for Castro's belated 80th birthday, also La Revolución, which is reaching 50." The commission did not rule on these complaints, saying that web text was outside its remit.
In a submission to the commission, the broadcaster had defended its series, saying that those who watched the whole evening's programming "were reminded at several points about Fidel Castro the dictator." SVT admitted, however, that "it would naturally have been better if freedom of speech on Cuba had been dealt with more comprehensively."
The Local contacted Lars Säfström, head of programming at SVT Malmö, which produced the theme evening. He said he had not yet been informed of the ruling.
"I prefer not to comment at present," he said.
The commission's decision must now be made public by SVT "in an appropriate manner."