The 1994 national census reported a total population for this woreda of 35,769, of whom 17,934 were men and 17,835 women; 562 or 1.57% of its population were urban dwellers at the time. The two largest ethnic groups reported in Seweyna were the Oromo (89.44%), and the Somali (7.56%); all other ethnic groups made up 3% of the population. Oromiffa was spoken as a first language by 91.58%, and 8.4% spoke Somali; the remaining 0.02% spoke all other primary languages reported. The majority of the inhabitants were Muslim, with 99.91% of the population having reported they practiced that belief.