Let
p be an odd prime and
q=pm, where
m is a positive integer. Let
ζq be a
qth primitive root of 1 and
be the ring of integers in
. In [I. Gaál, L. Robertson, Power integral bases in prime-power cyclotomic fields, J. Number Theory 120 (2006) 372–384] I. Gaál and L. Robertson show that if
52c4d7"">, where
is the class number of
, then if
is a generator of
(in other words
) either
is equals to a conjugate of an integer translate of
ζq or
is an odd integer. In this paper we show that we can remove the hypothesis over
. In other words we show that if
is a generator of
c40b28aea""> then either
is a conjugate of an integer translate of
ζq or
is an odd integer.