Aim: The aim of this study was to assess the effect of Calamari Oil on lipid profile levels in diabetes streptozotocin induced diabetic Rats.
 Study design: An experimental study.
 Place and duration of study: Animal House, Department of Applied and Environmental Biology, Rivers State University, Port Harcourt and University of Port Harcourt Rivers State, Nigeria, between February 2020 and August 2020.
 Methodology: Thirty Six (36) albino rats were purchased and allowed to acclimatize for two (2) weeks in the laboratory at the animal farm house of the Department of Animal and Environmental Biology, Rivers State University. They were fed the normal rat feed (Chow feed) and water was allowed ad libitum. The rats were weighed and randomly grouped into six (6) groups with six rats in each group. Group 1 (Negative control) was placed on normal diet while groups 2 to 6 were placed on a high fat diet (HFD) prior to the induction with Streptozotocin to achieve diabetes and the animals were treated according to their groupings for four weeks by means of oral gavage. The dose of Calamari Oil administered to the rats was extrapolated from human doses. The high fat diet was prepared by mixing the animal feed (Chow diet) with margarine in a ratio of 3:1. After each period of treatments, blood samples were collected from the rats at the end of the treatments via cardiac puncture by anaesthetizing the rats with chloroform after a six (6) hour fast. Fasting blood glucose was determined using the Glucose Oxidase method, lipid profile was analysed spectrophotometrically and Atherogenic coefficient (AC) and Castelli ratio index-1 level (CRI-1) were calculated. The GC–MS analysis of bioactive compounds from Calamari Oil was done using Agilent Technologies GC systems with GC-7890A/MS-5975C model. Data generated were analysed using SPSS version 22.0 of windows statistical package. Results were considered statistically significant at 95% confidence interval (p < 0.05).
 Results: The results showed that after week 1 - 4 of exposure, the mean TG (Triglyceride) value of the Negative control group (NC), Positive control (PC) group, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in mg/dl were 130.89 ± 2.52, 174.94 ± 3.11, 166.64 ± 1.95, 160.61 ± 0.60, 153.37 ± 2.24 and 141.62 ± 0.99 respectively. Mean TC (Total cholesterol) value of the NC, PC group, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in mg/dl were 160.93 ± 2.99, 194.96 ± 2.09, 188.18 ± 1.41, 180.63 ± 0.59, 169.96 ± 1.47 and 159.71 ± 1.43 respectively. HDL (High density lipoprotein) value of the NC, PC group, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in mg/dl were 83.05 ± 2.96, 65.68 ± 1.78, 66.97 ± 1.28, 72.75 ± 0.52, 76.35 ± 0.77 and 78.94 ± 0.86. Mean LDL (Low density lipoprotein) value of the NC, PC group, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in mg/dl were 51.7 ± 3.21, 94.3 ± 0.48, 88.15 ± 1.08, 75.76 ± 0.62, 62.95 ± 0.94 and 52.46 ± 0.59 respectively. The mean non- HDL cholesterol value of the NC, PC group, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in mg/dl were 159.93 ± 2.99, 193.96 ± 2.09, 187.18 ± 1.41, 179.63 ± 0.59, 168.96 ± 1.47 and 158.71 ± 1.42 respectively. Also, mean cholesterol ratio value of the NC, PC groups, diabetic groups exposed for weeks 1, 2, 3 and 4 expressed in mg/dl were 1.94 ± 0.07, 2.97 ± 0.06, 2.81 ± 0.04, 2.48 ± 0.02, 2.22 ± 0.01 and 2.02 ± 0.01respectively.
 Conclusion: Type 2 diabetes is associated with dyslipidemia and as such the treatment with the Calamari Oil in the treated groups had positive effect on lipid profile markers with TG, TC, LDL, AC, CRI-1 decreasing and HDL increasing with increase in duration of time.