The regression coefficients of the time-weighted AL index (ALw) to the Dst index are calculated for each year from 1966 to 1994. It is found that the slope of the linear regression equation varies over a period of 11 years: The coefficient a1 in a regression equation, Dst=a0+a1ALw, is maximized near the sunspot maximum and is minimized near the sunspot minimum. The long-term variations in the relationship between these indices and solar wind parameters are also examined. The dependence of Dst on the solar wind electric flux, BzV2, is nearly constant, while the values of AL for fixed values of BzV2 are greater at the solar minimum than at the solar maximum, where Bz and V denote the Z component of the interplanetary magnetic field and the solar wind speed, respectively. Possible causes that can account for these characteristics are discussed. ¿ 1999 American Geophysical Union