High spin states in the rare earth nuclei 161Er and 162Er have been populated via the fusion-evaporation reaction 130Te(36S, xn)166-xEr at a bombarding energy of 170 MeV. The Euroball array of escape-suppressed germanium detectors, situated at the I. N. F. N. laboratory in Legnaro, Italy, was used to detect prompt gamma-rays resulting from the depopulation of the excited states. In total, five rotational sequences have been observed to spins in excess of 40h. Two of these are in 162Er, in which the (+, 0) sequence has been extended to a spin of 56h and the (-, +1) sequence to a spin of 45h. The bands exhibit the regular energy spacing characteristic of prolate collective rotation. In 161Er, the (+, +1/2) , (-, +1/2) and (-, -1/2) bands are observed to exhibit irregularities in the rotational sequences at spins of 101/2+, 105/2- and 115/2- respectively. The former of these can be explained in terms of the crossing of unpaired bands in the absence of static neutron pairing correlations. Results for the negative parity sequences are compared with the predictions of calculations based on a cranked Nilsson-Strutinsky formalism and possible explanations for the observed behaviour are discussed. In addition, several new bands have been found in the two nuclei, and other known structures have also been extended to high spin. The behaviour of these bands is interpreted successfully within the formalism of the Cranked Shell Model.