Method for producing renewable base oil and diesel fuel from a feedstock of biological origin, the method comprising: a) providing a feedstock, the feedstock comprising 2-95 wt% of a mixture of free fatty acids; 5-98 wt% fatty acid glycerols selected from mono-glycerides, di-glycerides and tri-glycerides of fatty acids; and 0-50 wt% of one or more compounds selected from the list consisting of: fatty acid esters of the non-glycerol type, fatty amides, and fatty alcohols; wherein at least 50 wt% of the feedstock is made up of the mixture of free fatty acids and fatty acid glycerols; b) separating the feedstock into at least: - a free fatty acid feed having a higher concentration of free fatty acids than the feedstock, the free fatty acids comprising C 10 -C 24 fatty acids, preferably C 14 -C 22, such as C 14, C 16, C 18, C 20 and C 22 fatty acids; and - one or more free fatty acid depleted feed(s) having higher concentration of the compounds selected from mono-glycerides, di-glycerides and triglycerides of fatty acids, and having a higher boiling point than the free fatty acid feed; c) subjecting the free fatty acid feed to ketonisation reaction conditions where two fatty acids react to yield a ketone stream, the ketone stream comprising as the major part saturated ketones; wherein the ketonisation reaction conditions comprise a temperature in the range from 300 to 400 °C, a pressure in the range from 5 to 30 barg, a WHSV in the range from 0.25 - 3 h-1, and the presence of a ketonisation catalyst, and preferably the presence of a gas in the range from 0.1-1.5 gas/feed ratio (w/w), the gas being selected from one or more of: CO 2, H 2, N 2, CH 4, H 2 O; d) subjecting the ketone stream to both hydrodeoxygenation reaction conditions and to hydroisomerisation reaction conditions, simultaneously or in sequence, to yield a deoxygenated and isomerised base oil stream comprising the renewable base oil; e) optionally distilling the product of step d) to obtain a distilled renewable base oil; f) where the one or more free fatty acid depleted feed(s) is transformed into a diesel product by subjecting the one or more free fatty acid depleted feed(s) to both hydrodeoxygenation reaction conditions and to hydroisomerisation reaction conditions, simultaneously or in sequence, to yield a deoxygenated and isomerised diesel stream comprising the diesel fuel; g) optionally distilling the stream obtained from step f) to obtain a distilled diesel fuel. a) providing a feedstock, the feedstock comprising 2-95 wt% of a mixture of free fatty acids; 5-98 wt% fatty acid glycerols selected from mono-glycerides, di-glycerides and tri-glycerides of fatty acids; and 0-50 wt% of one or more compounds selected from the list consisting of: fatty acid esters of the non-glycerol type, fatty amides, and fatty alcohols; wherein at least 50 wt% of the feedstock is made up of the mixture of free fatty acids and fatty acid glycerols; b) separating the feedstock into at least: - a free fatty acid feed having a higher concentration of free fatty acids than the feedstock, the free fatty acids comprising C 10 -C 24 fatty acids, preferably C 14 -C 22, such as C 14, C 16, C 18, C 20 and C 22 fatty acids; and - one or more free fatty acid depleted feed(s) having higher concentration of the compounds selected from mono-glycerides, di-glycerides and triglycerides of fatty acids, and having a higher boiling point than the free fatty acid feed; - a free fatty acid feed having a higher concentration of free fatty acids than the feedstock, the free fatty acids comprising C 10 -C 24 fatty acids, preferably C 14 -C 22, such as C 14, C 16, C 18, C 20 and C 22 fatty acids; and - one or more free fatty acid depleted feed(s) having higher concentration of the compounds selected from mono-glycerides, di-glycerides and triglycerides of fatty acids, and having a higher boiling point than the free fatty acid feed; c) subjecting the free fatty acid feed to ketonisation reaction conditions where two fatty acids react to yield a ketone stream, the ketone stream comprising as the major part saturated ketones; wherein the ketonisation reaction conditions comprise a temperature in the range from 300 to 400 °C, a pressure in the range from 5 to 30 barg, a WHSV in the range from 0.25 - 3 h-1, and the presence of a ketonisation catalyst, and preferably the presence of a gas in the range from 0.1-1.5 gas/feed ratio (w/w), the gas being selected from one or more of: CO 2, H 2, N 2, CH 4, H 2 O; d) subjecting the ketone stream to both hydrodeoxygenation reaction conditions and to hydroisomerisation reaction conditions, simultaneously or in sequence, to yield a deoxygenated and isomerised base oil stream comprising the renewable base oil; e) optionally distilling the product of step d) to obtain a distilled renewable base oil; f) where the one or more free fatty acid depleted feed(s) is transformed into a diesel product by subjecting the one or more free fatty acid depleted feed(s) to both hydrodeoxygenation reaction conditions and to hydroisomerisation reaction conditions, simultaneously or in sequence, to yield a deoxygenated and isomerised diesel stream comprising the diesel fuel; g) optionally distilling the stream obtained from step f) to obtain a distilled diesel fuel.