The enzymatic synthesis of electrically conductive polyaniline comprises reacting one or more opt. substd. aniline monomers; an oxidising agent which comprises an enzyme peroxidase and an electron acceptor; and an effective acidifying agent having a pKa lower than that of the aniline monomers, in an acidic environment having a pH lower than the pKa of the aniline monomers, at 0-100C to form an electrically conductive polyaniline having more than 8 monomer units along the backbone of the polymer chain, having an electrical conductivity of at least about 10-6 S/cm as measured by the four-in-line probe technique. The solvent is selected from water, organic solvents or their mixts. The backbone of the polyaniline has the structure (I) where m = 1-5, with the proviso that n+m=5 and that at least one position on the aniline ring is a moiety which allows oxidative coupling at that position; n = 0-4; y = greater than or equal to 0; x = greater than or equal to 0, with the proviso that at least x or y is greater than 0 and that when x and y are greater than 0, the ratio x:y is greater than or equal to 0.5; z is selected such that the number of aniline monomer units along the polymer backbone is greater than 8; R1 = H; R2 = alkyl, alkenyl, alkoxy, cycloalkyl, cycloalkenyl, alkanoyl, alkylthio, aryloxy, alkylthioalkyl, alkylaryl, arylalkyl, amino, alkylamino, dialkylamino, aryl, alkylsulphinoyl, aryloxyalkyl, alkylsulphinylalkyl, alkoxyalkyl, alkylsulphonyl, aryl, arylthio, alkylsulphonylalkyl, arylsulphinyl, alkoxycarbonyl, arylsulphonyl, carboxylic acid, hydroxy, halogen, cyano, sulphonic acid, nitro, mercapto, alkylsilane or alkyl substd. with one or more of sulphonic acid, carboxylic acid, halo, nitro, mercapto, cyano or epoxy moieties, or any two R2 gps. may form an alkylene or alkenylene chain completing a 3-7C aromatic or alicyclic ring, which may opt. include one or more divalent nitrogen, sulphur, sulphonyl, ester, carbonyl or oxygen atoms; or R2 is an aliphatic moiety having repeating units of formula -(OCH2CH2)qO- or -(OCH2CH(CH3))qO- where q = positive whole number.    Also claimed is the polyaniline formed as above.    USE -   These polyanilines can be used for conductive polymer coated housings for sensitive electronic equipment (microprocessors), IR and microwave absorbing shields, flexible electrical conducting connectors, conductive bearings, brushes and semiconducting photoconductor junctions, antistatic materials for packaging electronic components, carpet fibres, waxes for floors in computer rooms and thin, optically transparent antistatic finishes for CRT screens, aircraft, car windows etc.    ADVANTAGE -   This process provides high molecular wt. polyanilines with a less toxic by-prod. or one that is easily sepd. and discarded, in a one-step process. There is no anion generated by the oxidising agent to compete with the acidifying agent so an excess of acidifying agent is not required. Undesirable side-prods. such as ammonium sulphate are not generated.