The presence of financial derivatives can be a very effective destabilizing factor in economies which are rapidly liberalized and which, especially, have poorly structured and improperly regulated imbalanced derivatives markets, like the emerging market economies, including Brazil in the 1990s. Since Brazil was subject to the rapid and almost complete liberalization of her economy in the 1990s, and had poorly structured imbalanced derivative markets, she was highly vulnerable to the harmful usages of financial derivatives in the 1990s. Although financial derivatives were initially developed for beneficial purposes, such as the handling of risks and volatilities, they turned into channels creating them. This paper aims to analyze and test statistically their potential role in the Brazilian financial crises in the 1990s through a time-series approach. The major findings indicate that they had an increasing impact on crisis pressures of Brazil in the 1990s, both in the short and long term.