Objectives: To determine the effectiveness of health intervention in improving the knowledge and attitude on toxoplasmosis among pregnant women with toxoplasma infection. Methods: Using randomized control trial study on pregnant women who attended the three randomly selected obstetric and gynecological clinics governmental hospitals in Al-Najaf. Respondents are divided into two groups; the Experiment and Control group. Data collection used self-administered questionnaire in the Arabic language and result analyzed using SPSS Version 21. Results: Out of a total 340 respondents, majority of them have low knowledge on almost all question items. There was not significant statistical difference in the level of knowledge between the two groups at baseline stage. At first post-test and second post-test, the knowledge score for the Experimental Group become better for all question items, compared to the Control Group. The difference in score improvement between the two groups was statistically significant. As for the attitudes, at baseline, the Experiment Group have more positive attitude compared to the Control Group (Experiment 52.4% and Control 47.6%), and there was not statistical significant difference between groups. At first post-test and second post-test, the level of attitudes for the Experimental Group become better, compared to the Control Group. The difference in the levels improvement between the two groups was statistically significant. Conclusion: Health intervention given to the Experimental Group was effective in increasing the score of knowledge and improve the attitude on toxoplasmosis compared to the Control Group.