Performance deficits during cerebellar intensive motor tasks maybe reflected by discrepant theta activity in the cerebral cortex. The present experiment examined the relationship between performance on a novel motor task and theta activity in adults with developmental dyslexia (DD) and an age- and IQ-matched control group (CG). Time-locked tonic and phasic lower and upper theta measures were derived and separate event-related theta band power (ERBP) scores were calculated for each of three experimental trials. The DD made significantly more errors than CG during Trials 1 and 2 of the motor task. Tonic theta did not differ between groups; however, the DD group displayed a significant decrease in ERBP across all trials and sites, specifically in central and parietal regions during Trial 3. No significant behavioral or physiological evidence supported the notion of conscious compensation (CC). Rather, deficient task performance in the DD group was associated with a general inability to recruit sufficient working memory processes.