Relic Gravitational Waves and Limits on Inflation

It is shown that only a narrow class of inflationary models can possibly agree with the available observational data on the anisotropy of the cosmic microwave background radiation (CMBR). These models may be governed by ``matter'' with the effective equation of state $-1.2 <p/ \epsilon < -0.6$ which includes the De-Sitter case $p/ \epsilon = -1$.