An automatic viscometer coupled with a GPC instrument is reported. The calculations which are briefly described give the molecular weight distribution corrected for long-chain branching effect, the variations of the structure parameter 9' and of the long-chain branching frequency 2 with molecular weight. We state the assumptions, among them the Zimm-Kilb formula for the conversion of hydrodynamic dimensions to geometric dimensions (O' = gx) with 0.5 as an exponent and a Zimm-Stockmayer formula giving in a second step 2 from g in the case of tetrafunctional branch points. The results on two samples of LDPE are presented in detail. The long-chain branching frequency increases with molecular weight in the region of high molecular weight. Other assumptions have been tested on the same LDPE samples with different values of x (1, 1.5, increasing with M.W.), tri-or tetrafunctionat branch points. These assumptions appear to give no differentiation between the products (no more variation of 2 with M.W.) and some theoretical reasons to exclude them are given. Another application of viscometer-GPC coupling is the direct determination of solution viscosity relations for linear polymers (HDPE, PB-I) without using absolutely characterized standards. Some observations about axial dispersion are given.