We consider equalization in cyclostationary interference, a situation which occurs in communication systems where neighbouring channels carry digital data at similar symbol rates, and where the interference is composed of a few dominant or phase-aligned interferers. A new minimum-mean-square performance bound has been derived for a continuous-time infinite-length decision-feedback equalizer in the presence of multiple cyclostationary interferers and additive white noise. This bound was evaluated in a subscriber-loop system example to show the performance improvements which can occur over the situation where the interference is stationary, but has the same mean power spectrum. Linear equalizer performance curves were also added to the comparisons. These results show two important techniques which can provide opportunities for improved equalizer performance in cyclostationary interference. The first is by decreasing the misalignment of the phases of the clocks at the central office. The second is by using transmitter-pulse bandwidths which are wide relative to the symbol-rate.