  We prove that for any two quasi-Banach spaces $X$ and $Y$ and any $\alpha>0$
there exists a constant $\gamma_\alpha>0$ such that $$ \sup_{1\le k\le
n}k^{\alpha}e_k(T)\le \gamma_\alpha \sup_{1\le k\le n} k^\alpha c_k(T) $$ holds
for all linear and bounded operators $T:X\to Y$. Here $e_k(T)$ is the $k$-th
entropy number of $T$ and $c_k(T)$ is the $k$-th Gelfand number of $T$. For
Banach spaces $X$ and $Y$ this inequality is widely used and well-known as
Carl's inequality. For general quasi-Banach spaces it is a new result.
