The present study investigates the effect of genre on lexical and syntactic complexity. The corpus used for this study is made up of argumentative and narrative texts from the TRAWL (Tracking Written Learner Language) online corpus. The study analyses texts written by 22 Norwegian EFL learners, 10 in year 8 and 12 in year 9. One narrative text and one argumentative text from each student is analysed using an automated method to calculate complexity based on one measure of lexical complexity, the Guiraud Index and two measures of syntactic complexity, mean length of sentence and mean length of t-unit. A qualitative analysis, comparing outlying results to the Swedish National curriculum, also gave insight into different levels of complexity. Previous studies suggest that narrative texts have more lexical complexity while argumentative texts are more syntactically complex. The results of this study support this hypothesis though not all correlations were found to be statistically significant.