Magnetization (M), field induced magnetic anisotropy (K_u), rotational hysteresis loss (E_rot) and melting point (T_m)f water- and paraffin-base ferrofluids were investigated in a temperature range from 77 K to 300 K as a function of the density of colloidal particles. Both paraffin and paraffin-base fluids were melted down at the temperature range from 180 to 210 K. In this range, the values of M and E_rot, for paraffin-base fluids increased and K_u decreased with increasing temperature. These properties are interpreted by assuming that liquid-state and solid-state parts in paraffin exist in this tempetarure range and that the volume of solid-state part decreases with increasing temperature. The freezing point depression was observed in water-base fluids.