diff --git a/src/smileyllama/score/__init__.py b/src/smileyllama/score/__init__.py
index 5d40bd4..706a798 100644
--- a/src/smileyllama/score/__init__.py
+++ b/src/smileyllama/score/__init__.py
@@ -6,6 +6,7 @@
 from .iminer_props import *
 from .vina import *
 from .normalizer import *
+from .clogs import *
 
 from .registry import REGISTRY
 
diff --git a/src/smileyllama/score/clogs.py b/src/smileyllama/score/clogs.py
new file mode 100644
index 0000000..0b46f6a
--- /dev/null
+++ b/src/smileyllama/score/clogs.py
@@ -0,0 +1,121 @@
+import os, math
+from typing import Optional, List
+from pathlib import Path
+
+import numpy as np
+
+from .base import Score
+from ..utils import safe_run_command
+
+
+class CLogS(Score):
+    """Score for aqueous solubility (cLogS) using the clogs_alteri executable.
+
+    Computes cLogS values for a list of SMILES by writing them to a .smi file,
+    invoking the clogs_alteri tool (which modifies the file in-place to append
+    tab-separated cLogS values), and parsing the results.
+    """
+
+    def __init__(
+        self,
+        exec_path: str = '/global/scratch/users/gbalteri/CACHE/calc_cLogS/clogs_alteri',
+        *,
+        wdir: Optional[os.PathLike] = None,
+    ):
+        """Initialize CLogS scorer.
+
+        Parameters
+        ----------
+        exec_path : str, optional
+            Path to the clogs_alteri executable.
+        wdir : os.PathLike, optional
+            Working directory for intermediate files. If None, must be set later.
+        """
+        super().__init__()
+        assert os.path.isfile(exec_path), f'{exec_path} not found'
+        self.exec = exec_path
+        if wdir is not None:
+            self.set_working_dir(wdir)
+
+    def write_smiles_file(self, smiles: List[str], path: os.PathLike):
+        """Write SMILES strings to a .smi file (one per line).
+
+        Parameters
+        ----------
+        smiles : list of str
+            SMILES strings.
+        path : os.PathLike
+            Output file path.
+        """
+        with open(path, 'w') as f:
+            for smi in smiles:
+                f.write(f'{smi}\n')
+
+    def parse_results(self, path: os.PathLike, n: int) -> np.ndarray:
+        """Parse cLogS results from the modified .smi file.
+
+        After execution, the file has a header line ``SMILES\\tcLogS`` followed
+        by tab-separated SMILES and score lines.
+
+        Parameters
+        ----------
+        path : os.PathLike
+            Path to the results file (modified in-place by clogs_alteri).
+        n : int
+            Expected number of results.
+
+        Returns
+        -------
+        numpy.ndarray
+            Array of cLogS scores. NaN for any lines that failed to parse.
+        """
+        scores = [math.nan] * n
+        try:
+            with open(path) as f:
+                lines = f.readlines()
+            # first line is the header "SMILES\tcLogS"
+            for i, line in enumerate(lines[1:]):
+                if i >= n:
+                    break
+                parts = line.strip().split('\t')
+                if len(parts) >= 2:
+                    try:
+                        scores[i] = float(parts[1])
+                    except ValueError:
+                        pass
+        except FileNotFoundError:
+            pass
+        return np.array(scores)
+
+    def compute_batch(self, smiles: List[str]) -> np.ndarray:
+        """Compute cLogS scores for a batch of molecules.
+
+        Parameters
+        ----------
+        smiles : list of str
+            List of SMILES strings.
+
+        Returns
+        -------
+        numpy.ndarray
+            Array of cLogS scores.
+        """
+        smi_path = self.wdir / 'input.smi'
+        self.write_smiles_file(smiles, smi_path)
+        safe_run_command([self.exec, str(smi_path)])
+        return self.parse_results(smi_path, len(smiles))
+
+    def compute(self, smiles: str) -> float:
+        """Compute cLogS score for a single molecule.
+
+        Parameters
+        ----------
+        smiles : str
+            SMILES string.
+
+        Returns
+        -------
+        float
+            cLogS value.
+        """
+        return self.compute_batch([smiles])[0].item()
diff --git a/tests/test_clogs.py b/tests/test_clogs.py
new file mode 100644
index 0000000..fd57e40
--- /dev/null
+++ b/tests/test_clogs.py
@@ -0,0 +1,24 @@
+import os, shutil
+from pathlib import Path
+
+from smileyllama.score.clogs import CLogS
+from smileyllama.utils import run_score_test
+
+cfg = [
+    ("clogs", CLogS, '/global/scratch/users/gbalteri/CACHE/calc_cLogS/clogs_alteri'),
+]
+
+test_smiles = [
+    'c1ccccn1', 'x', 'CN1C=C2C=C(C(=CC2=N1)Cl)NC3=NC(=O)N(C(=O)N3CC4=CC(=C(C=C4F)F)F)CC5=NN(C=N5)C',
+    'C' * 150
+]
+
+
+def test_clogs():
+    for tag, cls, exec_path in cfg:
+        print(f"===== Testing {tag} =====")
+        workdir = Path(__file__).parent / f'_test_{tag}'
+        if workdir.is_dir():
+            shutil.rmtree(workdir)
+        score_obj = cls(exec_path=exec_path)
+        print(tag, run_score_test(score_obj, test_smiles, wdir=workdir))