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SpecialtyMLS-C01Retired

AWS Machine Learning Specialty Exam Prep

The AWS Certified Machine Learning - Specialty (MLS-C01) validates expertise in building, training, tuning, and deploying machine learning models on AWS. This specialty certification covers the full ML lifecycle and is designed for data scientists and ML engineers with 2+ years of hands-on experience.

Note: Retired by AWS. Replaced by the ML Engineer Associate (MLA-C01).

This exam has been retired

The last day to take MLS-C01 was 31 March 2026. It is replaced by MLA-C01.

This exam can no longer be taken. Anyone who passed before the cutoff keeps the credential for three years from their earn date. If you want an AWS machine learning certification now, the path is the Machine Learning Engineer – Associate — but note that MLA-C01 is itself being replaced by MLA-C02 in late 2026, so check the timing before you book.

Confirm on the official AWS certification page
Duration

180 minutes

Questions

65 questions

Passing

750/1000

Cost

$300 USD

Exam Domain Breakdown

Data Engineering20%
Exploratory Data Analysis24%
Modeling36%
Machine Learning Implementation and Operations20%

MLS-C01 Practice Exam Questions

The MLS-C01 exam gives you 180 minutes for 65 questions, and you need 750/1000 to pass. Reading study notes does not tell you whether you would clear that bar today — only answering exam-style questions under the same conditions does.

Practice is most useful when it follows the exam blueprint rather than a random question bank. Modeling alone accounts for 36% of your MLS-C01 score, so a weak spot there costs you far more than an equivalent gap in a lighter domain. Practising by domain shows you where your points are actually leaking.

We no longer offer MLS-C01 practice exams

This exam has been retired, so practising for it would not get you a credential. If you are looking for an AWS certification in this area, start with a current exam instead.

See current AWS certifications

Who Should Take This Exam

  • Data Scientists
  • ML Engineers
  • AI Researchers
  • Data Analysts with ML experience

What to Expect on the MLS-C01 Exam

The ML Specialty exam is heavily weighted toward modeling (36%) and tests deep understanding of ML algorithms, model selection, hyperparameter tuning, and evaluation metrics. You'll need to know when to use different algorithms (linear regression, logistic regression, decision trees, XGBoost, neural networks, k-means, PCA) and understand concepts like bias-variance tradeoff, regularization (L1/L2), and ensemble methods.

The exploratory data analysis domain (24%) covers data visualization, feature engineering, handling missing data, dealing with imbalanced datasets, and statistical analysis. Data engineering (20%) tests knowledge of data pipelines, S3 data lakes, and data transformation. The MLOps domain (20%) covers SageMaker deployment, A/B testing, model monitoring, and retraining pipelines.

How to Prepare for ML Specialty

This exam requires strong ML fundamentals — you should be comfortable with the math behind common algorithms, not just how to use them. Review linear algebra basics (matrix operations), probability and statistics (Bayes' theorem, distributions), and optimization (gradient descent, loss functions). Then focus on SageMaker: built-in algorithms, training with custom containers, hyperparameter tuning jobs, and deployment options.

Practice questions that ask you to choose the right algorithm for a given problem: classification vs regression vs clustering vs anomaly detection vs NLP vs computer vision. Understand data preprocessing techniques: normalization, one-hot encoding, handling missing values, and dealing with class imbalance (SMOTE, oversampling, undersampling). Budget 8-10 weeks of study.

Career Value and Retirement Notice

The ML Specialty remains a respected credential that validates deep ML expertise on AWS. However, AWS is transitioning this certification — the ML Engineer Associate (MLA-C01) now covers many practical ML engineering topics, and the MLS-C01 is expected to retire. If you're deciding between the two, the ML Engineer Associate is the forward-looking choice for most professionals.

That said, if you already have deep ML/data science experience and want to validate it, the ML Specialty's focus on algorithm theory and model design may be more relevant to your work than the associate-level exam. Currently certified professionals will retain their credential through its validity period.

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Frequently Asked Questions

Is the AWS Machine Learning Specialty being retired?

Yes, the MLS-C01 is being phased out as AWS introduces the Machine Learning Engineer Associate (MLA-C01). If you're choosing between them, the MLA-C01 is the forward-looking choice. Currently certified professionals retain their credential through its validity period.

How hard is the AWS ML Specialty exam?

The MLS-C01 is one of the most technical AWS exams. Modeling is the largest domain at 36% and requires understanding of ML algorithms, hyperparameter tuning, and evaluation metrics. You need knowledge of both ML theory (bias-variance tradeoff, regularization, ensemble methods) and AWS services (SageMaker, Glue, Kinesis).

Should I take ML Specialty or ML Engineer Associate?

For most professionals, the ML Engineer Associate (MLA-C01) is the better choice — it's newer, focuses on practical ML engineering, and will remain active longer. The ML Specialty is more theoretical and algorithm-focused. Choose it only if you specifically want to validate deep ML/data science knowledge rather than engineering skills.

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