Recurrent relationships of general form A(x + k) = aA(x) + b were shown to be applicable to the approximation not only of values of most physicochemical constants of organic compounds (A) indicating monotonous or oscillating variations within different homologous series (x = n_C, k = 1 or 2), but also of the dependences of chromatographic retention parameters on the number of carbon atoms in homologue molecules (A = t_R, x = n_C) in gas and high performance liquid chromatography (HPLC). In these cases the values of argument (the number of carbon atoms in the molecule) are integer by definition, while the functions are discrete. Besides that, the same recurrent equations describe the temperature dependence of retention times of analytes under isothermal separation conditions in gas chromatography (A = t_R, x = T, k = ΔT = const) and the dependences of retention times on the concentrations of an organic solvent as an eluent component (A = t_R, x = C, k = ΔC = const) under isocratic separation conditions in HPLC, which are the examples of the functions of continuous arguments. Key mathematical properties of recurrences explaining us their promising applications in chemistry and chromatography are discussed. The method to apply recurrent equations to arbitrary, not necessary equidistant, values of continuous arguments is considered. Copyright © 2009 John Wiley & Sons, Ltd.