Abstract Beginning with the Supreme Court of Canada decision in R v. Marquard (1993), it has become increasingly more difficult for lawyers to have proposed psychological testimony admitted into evidence at trial. By reviewing several recent cases, the author shows how courts are applying legal rules of admissibility in cases where expert psychological evidence is being proffered. Drawing on the review of case law, the author provides useful recommendations that will help psychologists ensure that - when appropriate - their testimony will be held admissible by courts. The testimony in court of expert witnesses in general, and forensic psychologists in particular, is disappearing from Canadian criminal trials. With increasing frequency, at least in Ontario, trial judges are declaring the testimony of psychologists inadmissible. Unless psychologists understand and specifically address the current legal test for the admissibility of expert testimony, they will be denied access to this forum for their work, and the trial process will be denied the benefit of their analysis. The reduction in admissible forensic psychological testimony has been the result of a series of decisions from the Supreme Court of Canada and the Ontario Court of Appeal over the past six years. I review some of these decisions below. R v. Marquard (1993) The first of these cases was R v. Marquard. At issue was expert evidence that explains why children may or may not disclose abuse. The Court ruled that expert witnesses could not comment on the credibility of a witness. Also, expert evidence would only be admitted where the subject in issue was beyond the knowledge of the average juror. In the early morning hours of June 4, 1988, Debbie-- Ann LeBlanc, aged three and one-half years, suffered a severe facial burn. From her birth until the time of her injury, Debbie-Ann had lived with her grandmother, Mrs. Marquard. At trial, Mrs. Marquard and her husband testified that they discovered Debbie-Ann in the living room in front of a couch with her face down. A butane cigarette lighter lay beside the child on the couch. A cigarette, charred on one end and moist on the other, was also found. The child told them: Nanna, I tried to light a At trial 17 months later, Debbie-Ann gave unsworn testimony that Nanna put me on the stove. Mrs. Marquard was tried on charges of aggravated assault before a judge and a jury. Following two days of deliberations, the jury found her guilty. Mrs. Marquard was sentenced to five years in prison. On appeal, this was reduced to two years by the Ontario Court of Appeal. Mrs. Marquard's conviction was further appealed to the Supreme Court of Canada, which ordered a new trial. One of the reasons a new trial was ordered was the manner in which expert testimony had been admitted at the trial (R v. Marquard, 1993, pp. 216-217). One of the experts called as a witness at trial was Dr. Marcella Mian, then head of the Suspected Child Abuse Clinic of the Hospital for Sick Children in Toronto. Dr. Mian testified that, in her opinion, the child was lying when she said she had burned herself with a cigarette. She also testified with regards to the common behaviour of abused children: There's another reason [why children initially lie] which is that children who have been abused often feel that they are responsible for the behaviour that was done to them, for the injury tat was inflicted on them ... Therefore if the caretaker then takes them to the hospital and they're feeling that they did something wrong to elicit this punishment, they're certainly not going to want to tell the hospital staff that they did something wrong because they feel if my mom or whoever did this to me because of what I did, I wonder what these people who are strangers are going to do to me because of what I did. (R v. Marquard, 1993, pp.227-228) Madame justice McLachlin (as she was then) wrote the decision of the Supreme Court of Canada, which granted Mrs. …