In this study the same transgenic hsp16-1::lacZ strain of C. elegans (PC72) as in the previous studies (De Pomerai et al (2000) and Dawe et al (2006)) was exposed to higher intensity RF fields (1.8 GHz; SAR 1.8 W kg-1). For both continuous wave (CW) and Talk-pulsed RF exposures (2.5 h at 25 °C), there was no indication that RF exposure could induce reporter expression above sham control levels. However, some evidence that reporter expression may be reduced by 15% following exposure to either Talk-pulsed or CW RF fields were reported under conditions where background reporter expression was moderately elevated in the sham control.