Father is Mammadov Shamil Mamoy, mother is Mammadova Masma Rajab.
In 1965 Mammadov Garib successfully left secondary school in Amasia, in 1966 he entered geography-biological faculty of the Azerbaijan State Teachers Training Institute named after V.I.Lenin, where was a secretary of the "Komsomol" organization and a member of scientific and student's society.
In 1970 year after graduating from the Institute with honors, began his labor activity as the laboratory assistant in Scientific Research Sector of Erosion, then worked at Institute of Soil science and Agrochemistry of ANAS consistently in positions: junior scientist (1972–1980), senior scientist (1980–1984), head of the laboratory (1984–1994), director of the Institute (1994–2000).
In 1979 HAC USSR gave him with an academic degree of the doctor of philosophy on agrarian sciences, and in 1992 – Dr.Sci.Biol.
Garib Mammadov was elected a deputy of Milli Majlis (Parliament) of the Azerbaijan Republic (1996) in the I convocation.