The two most important secular political parties in the north were the Sudanese Communist Party (SCP) and the Baath. The SCP was formed in 1944 and early established a strong support base in universities and labor unions. Although relatively small, the SCP had become one of the country's best organized political parties by 1956 when Sudan obtained its independence. The SCP also was one of the few parties that recruited members in the south. The various religiously affiliated parties opposed the SCP, and, consequently, the progression of civilian and military governments alternately banned and courted the party until 1971, when Nimeiri accused the SCP of complicity in an abortive military coup. Nimeiri ordered the arrest of hundreds of SCP members, and several leaders, including the secretary general, were convicted of treason in hastily arranged trials and summarily executed. These harsh measures effectively crippled the SCP for many years.

Following Nimeiri's overthrow, the SCP began reorganizing, and it won three seats in the 1986 parliamentary elections. Since the June 1989 coup, the SCP has emerged as one of the Bashir government's most effective internal opponents, largely through fairly regular publication and circulation of its underground newspaper, Al Midan. In November 1990, Babikr at Tijani at Tayib, secretary general of the banned SCP, managed to escape from house arrest and flee to Ethiopia.

The Baath Party of Sudan was relatively small and sided with the Baath Party of Iraq in the major schism that divided this pan-Arab party into pro-Iraqi and pro-Syrian factions. The Baath remained committed to unifying Sudan with either Egypt or Libya as an initial step in the creation of a single nation encompassing all Arabic-speaking countries however, the Baath's ideological reservations about the existing regimes in those two countries precluded active political support for this goal. The Nimeiri and Bashir governments alternately tolerated and persecuted the Baath. The RCC-NS, for example, arrested more than forty-five Baathists during the summer of 1990. Restrictions against the Baath were eased at the end of year, presumably because Sudan supported Iraq during the Persian Gulf War.

Data as of June 1991