In this paper methods for determination of fentanyl (FL) and its three analogues: alfentanyl (AL), sufentanyl (SL) and remifentanyl (RL), atropine (AT) and scopolamine (SK) in biological material (whole blood and urine) using liquid chromatography atmospheric pressure chemical ionisation mass spectrometry technique (LC-MS/ APCI) are presented. Separation of analytes was performed in gradient conditions, using a LiChroCART LiChrospher 60 RP-select B column. The mobile phase consisted of 0.1% (v/v) formic acid in water and in acetonitrile. Target analytes were isolated from biological matrices using liquid-liquid extraction technique with n-butyl chloride or diethyl ether as extraction solvents. The validation data of the methods were: limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) - 0.05 and 0.25 ng/ml for FL, and 0.7 and 0.9 ng/ml for AT, both in blood, whereas 1.9 and 2.1 ng/ ml for FL, and 0.6 and 0.9 ng/ml for AT in urine. Calibration curves showed linearity in concentration ranges from LOQ to 25 ng/ml in blood and from LOQ to 50 ng/ml in urine. Determination coefficients (R2) of linear regression equation were higher then 0.98. Extraction recovery, intra-day precision (CV(w.g.)) and inter-day precision (CV(m.g.)) were determined at analytes and internal standard (I.S.) concentration of 5 ng/ml for blood, and at analytes and I.S. concentrations of 20 and 5 ng/ml, respectively for urine. Extraction recovery ranged from 76 to 100% for blood and 53--72% for urine. CV (n=5) and CV(m.g.) (n=15) equal from 4.8 to 7.5% and from 6.8 to 16.2% respectively for blood, and from 4.3 to 5.4% and from 5.8 to 9.5% for urine. The application of elaborated methods of the determination of FL, AT and SK in blood and urine for 8 expert opinions elaborated at the Institute of Forensic Research in Krakow is described. FL was detected and quantified in 3 cases, whereas AT and SK in 7.