This paper analyses trade union membership with respect to the Associa
tion of University Teachers representing academic and related staff in
the 'old' UK higher education sector, It therefore negates the diffic
ulties encountered with prior cross-sectional research concerning unio
nized and non-unionized workplaces and their homogeneity. Two models a
re estimated at the local association, or university, level where the
hypothesized variables encompass age and career related determinants,
staff gender divisions and a series of university-specific characteris
tics together with locational and political indicators. We find signif
icant influences upon union density include career grade, mean staff a
ge, male staff numbers together with the institution's classification.