Geochemical analytical data are reported for 123 Cretaceous rock samples from northwestern Alberta collected by Alberta Geological Survey (AGS) staff from 2001 to 2005. The values for one repeat analysis are included (5602R), making a total of 124 analytical records. The results include analyses of 57 mudstone, 29 shale, 13 ironstone, 6 pyrite (float), 5 kimberlite (including one till clast) and 5 sandstone (including one bioclastic sandstone) samples. Geochemical analyses were performed by Acme Analytical Laboratories Ltd. of Vancouver, British Columbia, for a wide range of elements and oxides using the following analytical methods. (a) Method 1EX: four-acid (HF-HNO3-HClO4-HCl) digestion and inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) multi-element analyses. (b) Method 1F: aqua regia digestion and inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) multi-element analyses. (c) Method 2A: carbonate carbon (CO2), graphitic carbon, organic carbon and sulphate determined using a Leco carbon-sulphur analyzer. (d) Method 4A: fusion-HNO3 digestion and inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses except for (i) total C and total S by Leco carbon-sulphur analyzer and (ii) loss on ignition (950 degrees C). (e) Method 4B: fusion-HNO3 digestion and inductively coupled plasma mass spectrometry (ICP-MS) analyses.