How to teach English as a second or foreign language has been heatedly debated as long as the subject has been taught. One of the many issues regarding the teaching of English as a second or foreign language is the issue of whether or not to teach grammar, and if we teach it, how should we go about it?   This study examines two different approaches to teaching English grammar at the Swedish upper-secondary school level. Experiments were conducted in four different groups of students (a total of 64 informants were used), all from the same upper-secondary school in a medium-sized Swedish city. The experiments were based on teaching the genitive construction to the informants during a 75-minute class. The results were analyzed mainly quantitatively with the help of test results from the 64 informants; the aspect of gender differences in the results was also analyzed.   According to the study, one of the approaches seemed to be slightly superior to the other. There were also factors (other than the test results) which may speak in favour of one approach rather than the other.