No general jus soli. By legal presumption, a child born in Burundi of legally unknown parents, and a child found in Burundi unless proven not born on Burundian soil, are Burundian (art. 3(a)-(b)). Ordinary nationality at birth is patrilineal under the 2000 statute (art. 2).
A foreign woman who marries a Burundian acquires nationality by simple declaration, made at any time during or after the celebration of a valid marriage (arts. 4, 10, 11). A foreign husband of a Burundian woman has no declaration route; he naturalises with the residence period reduced to five years (art. 7(d)).
Patrilineal at statute level (Loi 1/013 art. 2): Burundian by birth is the legitimate child of a Burundian father (even if born abroad), or the natural child whose filiation with a Burundian father is established. The mother transmits only where paternal filiation is not established or the child is disavowed by the father (art. 2(c)-(d)). A child of a Burundian mother and foreign father otherwise acquires by option (art. 5) or certain legal presumptions (art. 3(c)). Note: parent-equality language in the 2018 Constitution is not implemented in this statute.
At least ten years permanent residence in Burundi, reduced to five years for foreigners married to Burundian women and for foreigners who have rendered exceptional services (art. 7(d)). Other conditions: age 21+, good conduct and no crime/délit conviction, proven attachment to the Burundian nation and assimilation (art. 7(a)-(c)). Naturalisation is granted by presidential decree (art. 6) — discretionary. Naturalised persons gain electoral eligibility only ten years after publication (art. 9).
estimated, not read from law — Art. 7(d) confirms the ten-year floor previously labeled as modeled from comparative sources. Loi 1/013, B.O.B. n° 8 bis/2000.