Gustav Gerneth (born 15 October 1905) is, at age 113 years, 103 days, the world's oldest living man since the death of Japanese Masazō Nonaka on 19 January 2019.

He is also the oldest person ever to reside in Germany (and the fourth oldest German-born person ever behind Augusta Holtz, Charlotte Benkner and Luzia Mohrs) and the oldest living man in Europe since the death of Spaniard Francisco Núñez-Olivera on 29 January 2018 (however, Gerneth is still not fully verified).

He was born in Szczecin (known then as Stettin), Poland (then part of the German Empire)[2] He worked in a shipping company and at a gas plant. During World War II, he was a mechanic with the German air force (Luftwaffe). He married his wife Charlotte in 1930 (died in 1988) and the couple had three sons. The death of Luzia Mohrs, who was born on 23 March 1904 in Germany and emigrated to Brazil, on 16 October 2017 meant that Gerneth became the oldest living German person just one day after his 112th birthday.

Gustav Gerneth still lives by himself in Havelberg in Saxony-Anhalt in the same brick house with steep entrance stairs where he has lived for over forty years, with family members caring for his household. According to a statement by his granddaughter at his 113th birthday, he still has a lucid mind, watching football, solving crosswords and doing mental arithmetic.

Asked for the reason of his long life, he said:

“ Ich habe immer gut gelebt und gegessen. Keine Diät. Immer Butter, keine Margarine. Ich habe mein Leben lang keine Zigarette angerührt und Alkohol nur zu Feiern getrunken. ” “ I was always living and eating well. No diet. Always butter, never margarine. I have not touched any cigarette all my life and I drank alcohol just to party. https://en.wikipedia.org/wiki/Gustav_Gerneth