The purpose of this study was to determine the effectiveness of two water-based exercise programs on maximal isometric strength and body weight in postmenopausal women. 59 women were randomly assigned to swimming group (GN; n=21), shallow pool group (GPP; n=21) and control group (GC; n=17). Maximal isometric strength in a trunk extension (FIET) and in a knee extension (FIEP), and body mass index (IMC) was measured after one year of training. GPP and GC demonstrated a significant decrease (p<0,05) in FIET (-7,59N; -17,41N respectively) and FIEP (-10N; -25,46N respectively). Statistical differences between GN and GC were found respect to FIET and FIEP, and between GPP and GC respect to FIEP. IMC was significantly reduced in GN (-0,53 kg/m2) and GPP (-0.75 kg/m2). Water training is not effective regarding improvements on isometric strength in postmenopausal women but slows the age related muscle wasting and leads to positive changes in body weight.