  A search for duplicity of lambda Bootis stars has been made by using the
speckle camera installed at the Telescopio Nazionale Galileo. The operation
mode and the reduction procedure allow one to obtain not only the separation,
but also the magnitude difference between the components; the latter parameter
is fundamental for determining the degree of contamination from the secondary
component of a binary system and thus the importance of the veiling effect that
produces absorption lines weaker than normal. Two stars, HD 38545 and HD
290492, are close binaries with values of the separation and of the magnitude
difference such that only a composite spectrum can be observed. For another 15
lambda Bootis candidates, observed with negative results, the upper limits of a
possible companion separation are given.
