Poly(allylamine)-metal complexes with Co(II), Cu(II), and Ni(II) in conjunction with an ultrafiltration membrane were prepared. They were obtained varying the polymerlmetal ion ratio and the pH (1, 3, 5, 7). The viscosimetric behavior of these poly(allylamine)-metal complexes as well as the poly(allylamine) and mixture of poly(allylamine) with each metal ion was also studied. All the aqueous solutions showed a pseudoplastic behavior. However, it is not far away from that of Newtonian behavior. The viscosity depends strongly on the pH and on the metal salt concentration.