diff --git a/.env.example b/.env.example
index 5e54b56..b60b966 100644
--- a/.env.example
+++ b/.env.example
@@ -12,3 +12,6 @@ DATABASE_URI=postgresql://postgres:postgres@localhost:5432/atol_db
 JWT_SECRET_KEY=
 JWT_ALGORITHM=HS256
 # BACKEND_CORS_ORIGINS=["http://localhost:3000","http://localhost:8000"]
+
+# NCBI API key
+NCBI_API_KEY=
diff --git a/app/core/settings.py b/app/core/settings.py
index 9f7143f..d1134ff 100644
--- a/app/core/settings.py
+++ b/app/core/settings.py
@@ -37,6 +37,9 @@ class Settings(BaseSettings):
     ENVIRONMENT: Optional[str] = None  # Options: "dev", "prod"
     APP_VERSION: str = "dev"
 
+    # NCBI api key
+    NCBI_API_KEY: Optional[str] = None
+
     # Model config
     model_config = SettingsConfigDict(
         env_file=".env",
diff --git a/app/services/ncbi_taxonomy_service.py b/app/services/ncbi_taxonomy_service.py
index 32e303b..d9430fb 100644
--- a/app/services/ncbi_taxonomy_service.py
+++ b/app/services/ncbi_taxonomy_service.py
@@ -6,6 +6,8 @@
 
 import requests
 
+from app.core.settings import settings
+
 logger = logging.getLogger(__name__)
 
 # Adapted from:
@@ -55,12 +57,16 @@ def fetch_reports(
 ) -> list[dict[str, Any]]:
     """Fetch taxonomy report dicts for a batch of tax_ids."""
     url = build_taxonomy_url(tax_ids, endpoint)
-    logger.info("Fetching NCBI %s reports for tax_ids=%s", endpoint, tax_ids)
+    request_params = {}
+    if settings.NCBI_API_KEY:
+        request_params["api_key"] = settings.NCBI_API_KEY
 
+    logger.info("Fetching NCBI %s reports for tax_ids=%s", endpoint, tax_ids)
+    
     for attempt in range(1, max_retries + 1):
         try:
             with _ncbi_semaphore:
-                response = requests.get(url, timeout=timeout_seconds)
+                response = requests.get(url, timeout=timeout_seconds, params=request_params)
             response.raise_for_status()
             payload = response.json()
             reports = payload.get("reports", [])