A method for producing monofunctionalized dialkylphosphinic acids, esters and salts, which comprises a) reacting a phosphinic acid source with olefins in the presence of a catalyst A to form an alkylphosphonous acid, salt or ester b) reacting the resulting alkylphosphonous acid, salt or ester with compounds comprising C=C, C=O or C=N double bonds to form compounds of the type where R 1, R 2, R 3, R 4, R 5, R 6 are identical or different and are each independently H, C 1 -C 18 -alkyl, C 6 -C 18 -aryl, C 6 -C 18 -aralkyl, C 6 -C 18 -alkylaryl and X is H, Ca, Mg, Al, Zn, Ti, Fe, Ce, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, ethylene glycol, propyl glycol, butyl glycol, pentyl glycol, hexyl glycol, allyl and/or glycerol and where A is OH, NH 2 or O-CO-R 8 and R 8 has the same meanings as R 1 to R 6 and W is hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, phosphinic acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, palmitic acid, stearic acid, malonic acid, maleic acid, fumaric acid, tartaric acid, citric acid, ascorbic acid, trimethylborane, triethylborane, tributylborane or triphenylborane, where n represents an integer or fraction ranging from 0 to 4 and the catalyst A comprises transition metals and/or transition metal compounds and/or catalyst systems composed of a transition metal and/or transition metal compound and at least one ligand and where the method in step b) is carried out without the addition of a catalyst, or wherein compounds of the formula where A is O-CO-R 8 have the R 8 CO 2 Y moiety detached from them in the presence of a catalyst B, where the catalyst B exclusively comprises lithium, lithium hydride, lithium aluminohydride, methyllithium, butyllithium, tertbutyllithium, lithium diisopropylamide, sodium, sodium hydride, sodium borohydride, sodium hydroxide, sodium methoxide or sodium butoxide, potassium hydroxide, potassium methoxide, potassium ethoxide or potassium butoxide. a) reacting a phosphinic acid source with olefins in the presence of a catalyst A to form an alkylphosphonous acid, salt or ester b) reacting the resulting alkylphosphonous acid, salt or ester with compounds comprising C=C, C=O or C=N double bonds to form compounds of the type where R 1, R 2, R 3, R 4, R 5, R 6 are identical or different and are each independently H, C 1 -C 18 -alkyl, C 6 -C 18 -aryl, C 6 -C 18 -aralkyl, C 6 -C 18 -alkylaryl and X is H, Ca, Mg, Al, Zn, Ti, Fe, Ce, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, ethylene glycol, propyl glycol, butyl glycol, pentyl glycol, hexyl glycol, allyl and/or glycerol and where A is OH, NH 2 or O-CO-R 8 and R 8 has the same meanings as R 1 to R 6 and W is hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphonic acid, phosphinic acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, palmitic acid, stearic acid, malonic acid, maleic acid, fumaric acid, tartaric acid, citric acid, ascorbic acid, trimethylborane, triethylborane, tributylborane or triphenylborane, where n represents an integer or fraction ranging from 0 to 4 and the catalyst A comprises transition metals and/or transition metal compounds and/or catalyst systems composed of a transition metal and/or transition metal compound and at least one ligand and where the method in step b) is carried out without the addition of a catalyst, or wherein compounds of the formula where A is O-CO-R 8 have the R 8 CO 2 Y moiety detached from them in the presence of a catalyst B, where the catalyst B exclusively comprises lithium, lithium hydride, lithium aluminohydride, methyllithium, butyllithium, tertbutyllithium, lithium diisopropylamide, sodium, sodium hydride, sodium borohydride, sodium hydroxide, sodium methoxide or sodium butoxide, potassium hydroxide, potassium methoxide, potassium ethoxide or potassium butoxide.